Inside scoop on enterprise java and middleware technologies

Best practices for building cloud based applications

2011-03-24T22:07:00.000-07:00

I wrote another article outlining some best practices for building cloud based applications. You can read the article at http://www.devx.com/architect/Article/46602?trk=DXRSS_LATEST

I am writing this blog using my iPad and blogger is not iPad friendly

Cloud Computing for Java Developers

2011-03-21T11:38:00.000-07:00

I wrote an article Java Cloud Development: What Developers Need to Know at Developer.com. This provides an introduction to Cloud Computing from Java Developers perspective. You can read the article here.

EJB 3 In Action, 2nd Edition

2011-03-16T22:00:00.000-07:00

The second edition of EJB 3 In Action was announced recently. Ryan Cuprak joined as a new author of the book. Ryan and Reza are doing most of the work on the book. We have made a lot of changes in the content to include EJB 3.1 and other Java EE features such as CDI.
Here is the table of contents for the book:

Part I: Overview of the EJB landscape
1. What's what in EJB 3.1
2. A first taste of EJB 3

Part II: Working with EJB 3 components
3. Building business logic with session beans
4. Messaging and message-driven beans
5. EJB runtime context, dependency injection, and aspect oriented programming
6. Transactions and security
7. Scheduling and timers in EJB
8. Exposing EJBs as SOAP and REST web services

Part III: Using EJB 3 with JPA and CDI
9. JPA entities
10. Managing entities
11. Using CDI with EJB 3

Part IV: Putting EJB 3 into action
12. Packaging EJB 3 applications
13. EJB 3 testing
14. Designing EJB-based systems
15. EJB performance and scalability
16. EJB 3, Seam, and Spring
17. The future of EJB 3

Appendices
A. RMI primer
B. Migrating from EJB 2.1 to EJB 3
C. Annotations reference
D. Deployment descriptors reference
E. Installing and configuring the Java EE 6 SDK
F. EJB 3 developer certification exam
G. EJB 3 tools support

The book is available on Manning Early Release Program. You can join MEAP and help improve the program

Webinar: Event Processing for Java Developers

2010-11-08T09:00:00.000-08:00

I'll be speaking at a webinar Event Processing for Java Developers arranged by Starview Technology, Inc tomorrow (Nov 9) at 10am PST. Register here.

Introducing an Event Server Platform

2010-11-04T13:30:00.000-07:00

After working for about seven years shaping and evangelizing for a Java Application Server platform and J2EE, I decided to move on. For the last year or so I’ve been spending my energy shaping up the next-generation middleware platform for building, deploying, and managing event-processing applications.

Most vendors have focused on providing limited functionality such as windowing, filtering, and pattern matching, often known as Complex Event Processing (CEP).These vendors have also been targeting limited use cases in the Financial Services sector. As CEP did not take off, many vendors have buried their offerings inside their SOA and BPM solutions. However, I think event processing is pervasive inside all businesses. Whenever you tweet or send a text/sms it generates an event. Whenever you plug in your electric vehicle to the grid, whenever you have a power outage, or whenever a machine breaks down in a factory – events are generated. A smart business needs to analyze and exploit these messages to make the right decision to take the right decision at the right time. Many of the new generation of applications are being built using an event-driven paradigm and need a new generation of middleware platform named an Event Server Platform. In this article, I will introduce an event server platform.

What is an Event Server?

Why do you use an application server? Because you do not want to reinvent the wheel and take advantage of several services the application server provides to quickly build your application. An event server provides similar functionality for users to rapidly build and deploy event-processing applications – optimized for event processing. I will discuss why traditional application servers are not suitable for event processing in a future article. One of the key points here is that traditional application servers are optimized for request-response applications and not for event processing.

In all practical senses an event server is an application server optimized for event processing applications. Let us look at an example architecture. The following figure shows the architecture for the Starview Event Server that is built on OSGi:

You have to build an application before you deploy it to an event server. So you need tools and languages to build an application.

Development Tool

You will need to build, test, and debug your event-driven application and hence you will need an IDE. Here is an example of Starview ACE that uses a model-driven approach to build an event-driven application. Starview ACE is an Eclipse plug-in and application models are based on the Eclipse Model Framework:

Connectivity Adapters

You will need to capture an event stream at its source and in-bound adapters provide this connectivity. The event source can be a messaging system, SNMP traps, socket reader, log files, database updates, and so on. An event server provides out–of-the-box adapters to simplify reading event sources without much programming. The adapters also generate outbound events or integrate with third-party systems and resources for correlating events.

Programming Language aka Event Processing Language

In order to process the events you need an Event Processing Language. The CEP vendors often refer to Stream SQL as their EPL. However, as you know SQL is quite limiting in nature and you will need the full semantics of a programming language built for event processing that provides fast and efficient in-memory structures to represent complex data types, andin-stream processing and analytics. The Event Processing Language must provide the ability to maintain state and support the concept of an event-processing agent for implementing complex event-processing rules.

Also, you do not want your event-processing rules to be static in nature: you want to enable your business users to author rules. Hence the programming language must provide a foundation to develop Domain-Specific Languages.

Here is a typical architecture for such an Event Processing Language:

This diagram shows the architecture for the Star™ language.

You may ask, “where is Java in this equation?” The event servers must integrate with existing Java applications, and provide the ability to build applications using Java. You have to remember, though, that Java has its limits and you have to explore the capabilities provided by Event Processing Languages.

Distributed Application

Many of the event processing applications are distributed in nature and require event processing at the edge. These are prevalent in many use cases such as Quality of Service, Smart Grid optimization, and manufacturing automation, where you want to process events locally and filter out unnecessary events at the edge. The event server platform must provide mechanisms to deploy a lightweight version of the event server at the edge and collaborate with a centralized event server without requiring hundreds of lines of code!

Management Infrastructure

You need a good management infrastructure for managing your event servers and applications. This becomes challenging when applications are distributed in nature. The management infrastructure should provide the ability to deploy, manage, and monitor applications, event servers, and server groups. And the infrastructure must be built using an event-driven paradigm.

The following screen shot shows the management console for Starview Enterprise Hub that provides such a management infrastructure:

These are the basics of an Event Server Platform. You will several advanced features such as high-availability, caching, etc.

We will discuss some of these topics in detail in future blog entries.

Bye!
References and Suggested Reading

Event Processing In Action
Starview Enterprise Platform
Attend my web seminar on Nov 9, 2010 Event Processing for Java Developers

SOA Management - Sample Chapter from Middleware Management Book

2010-01-12T12:11:00.000-08:00

Oracle Technology Network published sample chapter SOA Management (Oracle Service Bus) of my Middleware Management book.

You can access the chapter at http://www.oracle.com/technology/books/pdfs/sample-soa-management.pdf

This book covers management of both Oracle Fusion Middleware (WebLogic/OC4J, SOA Suite, IDM, Coherence, Forms/Reports, etc. and non-Oracle Midddleware such as JBoss, Tomcat, Apache Http Server IBM WebSphere and Microsoft .Net/IIS, etc

You can purchase the book at Amazon at http://www.amazon.com/Middleware-Management-Enterprise-Manager-Control/dp/1847198341.

Also see details at http://www.packtpub.com/middleware-management-with-oracle-enterprise-manager-grid-control-10g-r5/book

Should Java be free from Sun/Oracle?

2009-11-17T22:17:00.000-08:00

There was an interesting blog from SAP CTO “Freedom of Java”! He has a very absurd comparison of freeing Java from Sun/Oracle’s clout with falling of Berlin wall. Should we free Java from Sun? My answer is an emphatic No! I have been a Java enthusiast for about a decade. Although I never liked Sun’s control over Java/JCP, I have to admit that Java flourished under Sun’s stewardship. I hope Sun/Oracle will continue the leadership in taking Java to the next level. Oracle once claimed they support 300% Java! As an ex-employee of Oracle I know that Oracle’s business is completely dependent on success of Java, all of fusion middleware, applications, management products (enterprise manager) developed in Java. Oracle cannot gamble or bungle on Java. SAP’s concern seems to be too unjustified and seems to be politically motivated.

They are suggesting that Java/JCP should be freed from Sun/Oracle and controlled by some independent consortium (Java foundation) and have volunteered to throw money, time and energy behind Java. I don’t think SAP has contributed much to Java community in the past 15 years, besides furthering its own NetWeaver platform to attract developers to their proprietary application platform.

Interestingly enough they claim to have Java EE 5 certification for past two years. Note that Java EE 5 was finalized about two and half years back. I think they still do not have a production version of application server that supports Java EE 5. I could not find in their website about their production support even for J2EE 1.4. Their website still claims support for J2EE 1.3 as shown below:
http://www.sap.com/platform/netweaver/standardssupport/java.epx

They still have a developer preview for Java EE 5 at http://www.sdn.sap.com/irj/scn/downloads?rid=/library/uuid/00846edd-355b-2b10-f38c-df94ec96eb74

How can we believe that SAP will pump millions of dollars to an open consortium to support Java’s future growth when they have not invested money to build an application server that supports latest Java standards? I think they are just playing a devil’s role here to complicate matters with Oracle’s pending acquisition of Sun.

Without strong leadership, Java will perish. If we leave it to open source then it may fork and we will end up with several Java flavors and that will be a death blow to Java. Sun has invested billions of dollars on research, development and building the community around Java and should control it. If Oracle’s acquisition of Sun succeeds then Oracle should control Java/JCP, if it fails for some reasons then who should take over Sun (if SAP does!) should own Java!

That’s my 2 cents!

Book: Middleware Management with Enterprise Manager Grid Control

2009-10-06T21:46:00.000-07:00

I coauthored another book Middleware Management with Oracle Enterprise Manager with Arvind Maheshwari. This covers managing both Oracle Fusion Middleware and non-Oracle Middleware such as IBM WebSphere, JBoss, Microsoft Middleware with Oracle Enterprise Manager.

My JavaOne Presentation:

2009-06-02T11:24:00.000-07:00

I'm co-presenting with my co-author (EJB 3 In Action) Reza Rahman on JPA Application Tuning.

Here are details for the talk:

TS-3977 -Keeping a Relational Perspective for Optimizing the Java™ Persistence API

Thursday June 04 4:10 PM - 5:10 PM Hall E 134

If you are attending JavaOne this year, please attend the presentation. Also we have a book signing scheduled tomorrow (Wednesday June 3, 2pm at Java Book Store) so stop by if you want your book to be signed

-Debu

Using Quartz Scheduler on WebLogic Server

2009-01-09T10:47:00.000-08:00

I'm not a Quartz expert but I keep on getting emails with Quartz questions as one of my blog was published as a featured article at TheServerSide.com 4-5 years back. I got some questions on using Quartz on WebLogic Server recently. I modified the original example to run on WebLogic Server.

You can download this sample from here.

The Example

1. This sample uses TestEJB which is a stateless bean that has yourMethod that need to be scheduled as a job/service.

2. This method execution is scheduled as a Job from from QuartzManagerBean which is EJB 3.0 Session bean.

3. A Generic Servlet QuartzServlet uses dependency injection to invoke the QuartzManager from its init() method.

4. The QuartzServlet is automatically loaded using load-on-start mechanism. Hence as soon as the application is deployed - the job will be submitted .

How to Run the Example

1. You can download the code example from here.

2. This is designed to be deployed in the exampleServer. If you want to deploy in a different domain/server you have to make appropriate changes to common.xml

3. Start your WebLogic Server. Unlike OC4J that requires –userThreads, no special parameter or flag is required for WebLogic to run the example.

4. Set your environment variables. If you are using examplesServer, you can use %BEA_HOME%\wlserver_10.3\samples\domains\wl_server\setExamplesEnv.bat script to set environment variables required to compile and deploy the application

5. To compile and deploy, just run

ant

You will see the application to be deployed in console where WebLogic Server was started.

Jan 9, 2009 10:45:54 AM org.quartz.plugins.management.ShutdownHookPlugin initialize

INFO: Registering Quartz shutdown hook.

Jan 9, 2009 10:45:54 AM org.quartz.simpl.RAMJobStore initialize

INFO: RAMJobStore initialized.

Jan 9, 2009 10:45:54 AM org.quartz.impl.StdSchedulerFactory instantiate

INFO: Quartz scheduler 'WebLogicQuartzScheduler' initialized from default resour

ce file in Quartz package: 'quartz.properties'

Jan 9, 2009 10:45:54 AM org.quartz.impl.StdSchedulerFactory instantiate

INFO: Quartz scheduler version: 1.3.0

Jan 9, 2009 10:45:54 AM org.quartz.core.QuartzScheduler start

INFO: Scheduler WebLogicQuartzScheduler_$_one started.

Invoking EJB to schedule Job ..

0 0/5 * * * ?

Scheduling Job ..

0 0/5 * * * ?

Timer scheduled now ..

Generating report

Report Generation Completed

Hope this helps!

Article:Managing Complexity with BPEL Environment

2008-11-13T08:17:00.000-08:00

SOA World published an article on BPEL Management written by me with Arvind Maheshwari.

You can read the article: Managing Complexity with BPEL Management!

Enterprise Java – State of the World!

2008-11-06T02:02:00.000-08:00

One of my friends commented: “Java is no longer cool! Not hot either! What is the current state of enterprise Java?”

First it was .Net and then came a bonanza of scripting languages such as Ruby. All these technologies were there to eclipse the popularity of Java and J2EE. The hypes for these technologies were short-lived. The forecast for demise of Java EE was highly exaggerated. Java and J2EE still lives on!

I divide the players in the enterprise Java markets primarily into two buckets. The commercial vendors selling J2EE application server and the vendors building open source and so called free products. However a third force is emerging that is looking to disrupt the J2EE market space.

The commercial market space is now officially two horses’ race after Oracle acquired BEA. The battle is still on for the two traditional rivals! One application server (WebLogic) is stylish and always ahead with emerging technology and the other one proprietary loaded (Websphere) with the old baggage. Java EE 5 finalized in June 2006 and IBM Websphere just got certified with Java EE 5. That’s more than two years since the spec was finalized. That’s not strange though. JBoss that still do not have a production release that is Java EE 5 certified. Although they announced it's arrival more than a month back, I do not see a production version available as yet. They have a release candidate!

Now that we discussed JBoss’s certification issue let us look at the open source products. About two years back JBoss was the crown prince in the open source market. None of the other products Jonas, Glassfish or Geronimo had capabilities to challenge its supremacy. However JBoss lost the momentum in past year and half after being acquired by RedHat. Glassfish has gained a significant mindshare in last year and half thanks to their quality Java EE 5 implementation. I think the delay in shipping a quality Java EE 5 implementation by JBoss was a primary reason. Geronimo has not gotten much traction! However we should not forget that many customers still use Tomcat with just web applications. Although Tomcat does not have all bells and whistles of Java EE – it is still the most dominant open source container.

I put Spring in the third bucket. Spring is a great framework that makes application development simple. Java EE 5 borrowed a lot of great ideas from the Spring framework. Spring Framework certainly helped enterprise Java to go further. SpringSource, the company behind Spring Framework launched their OSGi-based application server named Spring dm Server. Spring dm Server not only competes with other application server vendors in the market. It also competes with Java EE! It allows you to deploy WAR modules and OSGi bundles. It is at its first version and lacks good high availability, manageability features. SpringSource hopes to implement part of Java EE 6 specs. If they are successful – Spring dm Server may be a disruptive force for the Java EE application server market. I will blog about my first impressions on Spring dm Server (write capabilities and limitations) in my upcoming blog.

Many people have raised concerns about slow adoption rate of Java EE 5. Is the slow adoption by two major players (IBM and JBoss) inhibiting the adoption rate for Java EE 5? Possibly! However we have to remember that for most companies, generating revenue is more important than the underlying technology. Many customers have deployed their applications using J2EE 1.4 and they achieved their performance and scalability goals so they cannot just throw those away and jump on to the Java EE 5 bandwagon. Having said that many customers are using Java EE 5 only with new development projects. The sales of my book has picked up lately.

With economy going down south- budgets for new projects are limited! Having said that Java is still the leading platform for building enterprise applications.

The JCP team is gearing up to finalize Java EE 6 by JavaOne 2009. This gives a fuzzy feeling that enterprise Java is still thriving. What do you think?

Using EJBContext from an EJB 3 Interceptor

2008-07-30T01:44:00.000-07:00

I got a question from a customer that he wants to use EJBContext from an EJB 3 Interceptor.

Yes, it’s very simple. Just inject the EJBContext into the interceptor using @Resource injection.

See the example code that uses methods of SessionContext as follows:

package actionbazaar.buslogic;

import javax.annotation.Resource;
import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;

public class CheckPermissionInterceptor {
@Resource
private javax.ejb.SessionContext ctx;

@AroundInvoke
public Object checkUserRole(InvocationContext ic) throws Exception {
System.out.println("*** CheckPermission Interceptor invoked for "
+ ic.getTarget() + " ***");
if (!ctx.isCallerInRole("admin")) {
throw new SecurityException("User: '"
+ ctx.getCallerPrincipal().getName()
+ "' does not have permissions for method "
+ ic.getMethod());
}
return ic.proceed();
}
}

If you want the run-able version of the example code, you can download from http://manning.com/panda and look at Chapter 5 example.

My Sessions at Oracle Open World 2008

2008-07-28T23:31:00.000-07:00

I’ve two sessions at Oracle Open World 2008, San Francisco. Here are my session details:

S298520 : Best Practices for Managing Your Oracle WebLogic Environment with Oracle Enterprise Manager
Track: Application Server and Transaction Processing
Room: Rm 2006
Date: 2008-09-22
Start Time: 11:30

S298522 : Top Five Things DBAs Must Know About Managing Middleware
Track: Application Server and Transaction Processing
Room: Rm 2003
Date: 2008-09-25
Start Time: 15:00

See you at San Francisco!

EJB 3 In Action available at Safari Online

2008-07-18T01:37:00.000-07:00

If you enjoy reading online then it's a good news for readers of EJB 3 in Action. It is now available online at Safari

Introduction to EclipseLink

2008-07-07T02:24:00.000-07:00

Doug Clarke has written a nice article that introduces EclipseLink.

EJB 3 Stateless bean Web service in WebLogic Server

2008-06-26T03:39:00.000-07:00

I recently got some questions from customers about the procedure for deploying EJB 3 Session Bean Web service in WebLogic 10. In this blog, I will outline the steps.

First develop your EJB3 session bean web service as follows:

@WebService(name="PlaceBid",
serviceName="PlaceBidService", portName = "PlaceBidPort",
targetNamespace = "http://actionbazaar.com/xml")
@SOAPBinding(style = SOAPBinding.Style.DOCUMENT)
@PersistenceContext(unitName="actionBazaar",name="actionBazaar")
@Stateless
public class PlaceBidBean {

@WebMethod

public Long addBid(String userId, Long itemId, Double bidPrice) throws BidException {

….

}

Deployment

Unlike OC4J, WebLogic do not support parsing of JAX-WS annotations at deployment time and if you try to deploy the compiled EJB 3 Web service, you will get deployment time exception. You have to run the EJB 3 WS thru annotation parsing tool (jwsc –java web services compile) supplied with WebLogic to generate the artifacts and package in your ejb-jar module.

Here is an example ant task to create the web service:

<target
name="build-ws-server" description="Target that builds the
target Web Service">
<jwsc
srcdir="${src.ejb.dir}"
destdir="${bld.service.dir}"
classpath="${common.j2ee.class.path}"
fork="true"
keepGenerated="true"
deprecation="${deprecation}"
keepTempFiles="true"
listfiles="true"
debug="${debug}">
<jws
file="actionbazaar/buslogic/PlaceBidBean.java" type="JAXWS"
explode="true"/>
</jwsc>
</target>

<target name="package-ejb"
depends="compile-ejb-classes,build-ws-server">;

<mkdir dir="${bld.ejb.dir}/actionbazaar/buslogic/jaxws" />

<copy todir="${bld.ejb.dir}/actionbazaar/buslogic/jaxws">

<fileset dir="${bld.service.dir}/actionbazaar/buslogic/PlaceBidBean/actionbazaar/buslogic/jaxws" includes="*"/> </copy>
<echo message="-----> Create EJB jar file"/>
<jar jarfile="${bld.ear.dir}/${ejb.name}.jar">
<fileset dir="${bld.ejb.dir}" includes="**" />
</jar>
</target >

Make sure to package the generated artifacts in the EJB JAR and then deploy the EJB-JAR or EAR to the WebLogic Server. Note that if your web service depends upon custom Java objects - the generated artifacts contain duplicate Java classes that you already may have. These duplicated classes are on a separate package structure and cause ClassCastException for me. So I avoid packaging these classes.

Accessing EJB 3 Web service

After successful deployment you can access the web service as follows:

http://hostname:port/ejb-name/web-service-name?wsdl

http://localhost:7001/PlaceBidBean/PlaceBidBeanService?wsdl

Hope this helps.

You can download the working examples from here. Chapter 15 contains web services example.

EJB 3, JPA, Web Services and Spring Examples for WebLogic Server

2008-06-20T04:02:00.000-07:00

Finally I was able to complete porting of all book examples of EJB 3 In Action to run on WebLogic Server.

You can download these from here

These contain a host of examples on EJB 3, JPA, Web Services and Spring Framework. Now we have complete examples for four servers: Glassfish, OC4J, WebLogic and JBoss.

Note that I tested the examples with an Oracle XE database. For simplicity, the examples are configured to use the exampleServer and default PointBase DB that is shipped with it. However some of these examples will properly not on PointBase because it does not support DB Sequence.

All chapters have the common domain model based on our famous ActionBazaar Application

Chapter 5: EJB 3 Interceptors, Timers
Chapter 8: O-R Mapping Annotations
Chapter 9: Entity Manager API
Chapter 10: JPQL and Native SQL Queries
Chapter 11: O-R Mapping with XML
Chapter 12: EM API from Web Tier, Java SE
Chapter 13: Extended Persistence Context
Chapter 15: EJB 3 Web services
Chapter 16: Spring with EJB 3 and JPA

Please try these out and let me know if you find any bugs!

EJB 3 Dependency Injection Refcard

2008-06-02T04:22:00.000-07:00

I wrote a Reference Card on EJB 3 Dependency Injection for Developer Zone. This is a quick reference card that describes metadata annotations and XML descriptor elements that you use for injecting resources and services.

You can access this reference card for free from Developer Zone at http://refcardz.dzone.com/refcardz/dependency-injection-in-ejb3

EJB 3 In Action Code Examples on WebLogic 10

2008-04-29T05:26:00.000-07:00

In my previous blog, I made the code examples available for first four chapters of EJB 3 In Action for WebLogic 10. However I did not provide you instructions to run these examples (Chapter 2-4) for WebLogic 10.

Chapter 2 example has a stateless session bean, stateful session bean, an MDB and a JPA Entity. The JPA persistence unit requires a JDBC DataSource and the Stateful/MDB uses a JMS queue.

Chapter 3 depends upon a JDBC DataSource and Chapter 4 uses JDBC DataSource and a JMS Queue.

I’ve provided a build script to configure these resources on the default examplesServer that gets created when you install WebLogic 10.

Download examples from here and unzip to a directory say c:\ejb3inaction\weblogic

Set the environment variables for your server as follows:

%BEA_HOME%/wlserver_10.0/samples/domains/wl_server/setExamplesEnv

Change to your directory to the directory

cd c:\ejb3inaction\weblogic

ant CreateResources

This will configure resources such as JDBC DataSource, JMS Connection Factory, Queues, etc.

4. To deploy the application, you can use WLS Admin Console. If you prefer you can use ant to deploy the application for a specific chapter.

cd chapter2
ant

To run the application client:

ant run

Hope this helps! I'm working on porting rest of the examples and will make these available sooner.

Diagnosing Production Java applications with AD4J

2008-04-17T04:21:00.000-07:00

One of my applications that uses EJB 3 and JPA was running much slower today and I had no clue what was going on. It is a very simple application to manage service requests. When I was trying to update some data for a service request – it was taking ever. Also searching of service requests by some search criteria was taking much longer than it does.

So I thought I would give Oracle AD4J a spin and will try to find out what is going! It is good that Oracle AD4J does not require any code changes in application, because it does not use byte code instrumentation. Nor does it require to restart/redeploy the application – so it was a perfect fit.

And it really helped diagnose the problem by me get into bottom of the issues. It was indeed a DB issue as I had initially suspected.

I will not bore you with installation and configuration steps of AD4J – rather I will outline how AD4J helped me diagnose the issue.

Finding the Offending Thread

As soon as I logon to AD4J console and clicked to view active threads – it showed all threads with the correct state and I saw one thread is with status “DBWait”.

That gave me an indication that something going fishy in the database request from from JPA provider.

Finding DB issue

When I clicked on DB Wait link to view details, it became clear that the transaction is running into some row lock contention with another user session.

Finding the SQL statement

Interestingly it allowed to me to view the SQL Statement that is taking forever by clicking the SQL hash. My application uses JPA 1.0 and I could view the SQL statements causing problem without increasing the log level from my JPA provider as in the following figure:

It also helped me find the other session that held the lock. Apparently we found that it was a batch process that was hanging for some reasons. After the hanging session was killed the application ran like a champ again!

Also I found that the JPQL query for retrieving SRs was running slower because of some missing indexes on the column and it was making a full table scan. Nice, it also AD4J allows to run explain for sql statements.

Downloading AD4J

You can download AD4J from OTN (http://www.oracle.com/technology/software/products/oem/htdocs/jade.html)

Installing AD4J Console and agents

Installing AD4J Console is easy. You can follow this guide to do this installation of AD4J Console and agent.

After you deploy the agent you are good to go. Your JVM for application server will be automatically discovered in the console.

The AD4J agent is a WAR file that needs to be deployed to the server. You can follow the instructions in the install guide to install the agent in favorite application server. I was using my favorite container OC4J, however it supports BEA WebLogic, IBM Websphere, JBoss, and Tomcat. You can run AD4J also with standalone Java.

If you want to trace the problem to the DB tier you can install the DB Agent. You can follow the instructions in this guide.

I will play around with AD4J and blog little more about its feature in future. In the meantime you can review it's usage scenario documented in here.

My interview @Java Lobby

2008-04-15T09:23:00.000-07:00

Java Lobby just published my interview with them. You can read this here.

Using JMX to Start/Stop Message Driven Bean

2008-03-31T01:52:00.000-07:00

OC4J 10.1.3.x allows users to start/stop MDBs dynamically without having recycle container or application.

For example, you can disable an MDB upon start/deployment by adding enabled="false" in your orion-ejb-jar.xml as follows

<message-driven-deployment name="MessageLogger" enabled="false">

MDB will not start when the application is deployed/started.

You can use Application Server Control to start the MDB later as shown in the following screen shot:

You may want to perform this operation from command line. You can download this zip file that contains code to stop/start MDB using JMX.

Unpackage the zip and change ant-oracle.properties file to change your URL, userid and password

Set ORACLE_HOME to the directory where OC4J installed

To start your MDB:

ant start -DappName=ejb30mdb -DejbModule=ejb30mdb-ejb -DmdbName MessageLogger

To stop it

ant stop -DappName=ejb30mdb -DejbModule=ejb30mdb-ejb -DmdbName MessageLogger

Following is the code snippet from the Java Class that perform the stop/start operation:

StartStopMDB mdb = new StartStopMDB();

try {

mdb.connect("service:jmx:"+args[0], args[1] ,args[2] );

System.out.println(mdb);

System.out.printf("Client connected? %s\n",mdb.isConnected());

MBeanServerConnection mbs = jmxCon.getMBeanServerConnection();

String objName = "oc4j:j2eeType=MessageDrivenBean,EJBModule=\""+args[4]

+"\",J2EEApplication="+args[3]+",J2EEServer=standalone,name=\""+args[5]+"\"";

ObjectName myMDBObjectName = new ObjectName(objName);

MessageDrivenBeanMBeanProxy MDBMBean =

(MessageDrivenBeanMBeanProxy)MBeanServerInvocationHandler.newProxyInstance(mbs,

myMDBObjectName, MessageDrivenBeanMBeanProxy.class, false);

if (args[6].equals("start"))

{

System.out.println("Starting up MDB: "+args[5] +" in ejb module:"+args[4]+

" in application name:"+args[3]);

MDBMBean.start();

System.out.println("Successfully started MDB!");

}

else if (args[6].equals("stop")) {

System.out.println("Stopping MDB: "+args[5] +

" in ejb module:"+args[4]+ " in application name:"+args[3]);

MDBMBean.stop();

System.out.println("Successfully started MDB!");

}

mdb.close();

} catch (Exception e) {

e.printStackTrace();

}

Hope this helps!

Using TopLink Essentials as the JPA Provider for WebLogic 10

2008-03-26T10:35:00.000-07:00

A couple of weeks ago, one customer asked me for instructions for using TopLink Essentials as the JPA provider with WebLogic 10. I thought I would give it a try as I’m working on migrating my book examples to WebLogic 10.

First, you have to download TopLink Essentials either from OTN or Glassfish web site.
I packaged the toplink-essentals.jar, toplink-essentials-agent.jar in the lib directory for the EAR so the structure of EAR looked like as follows:

chapter2-ejb.jar
lib/toplink-essentials.jar
lib/toplink-essentials-agent.jar

I specified provider class oracle.toplink.essentials.PersistenceProvider
in my persistence.xml packaged in my EJB module as follows:

<persistence-unit name="actionBazaar">
<provider>
class oracle.toplink.essentials.PersistenceProvider
</provider>
<properties>
<property name="toplink.ddl-generation" value="create-tables"> <property name="toplink.ddl-generation.output-mode" value="database">

If you want to use container managed entity manager with WebLogic’s JTA transaction manager you have to create your server platform class by extending oracle.toplink.essentials.transaction.JTATransactionController as follows:

package debu.weblogic;
import javax.transaction.TransactionManager;
import oracle.toplink.essentials.transaction.JTATransactionController;

public class WebLogicTransactionController extends JTATransactionController
{

private static final String WLS_TRANSACTION_MANAGER_NAME = "javax.transaction.TransactionManager";
public WebLogicTransactionController(){

}

protected TransactionManager acquireTransactionManager() throws Exception {
TransactionManager tm = (TransactionManager)jndiLookup(WLS_TRANSACTION_MANAGER_NAME);
return tm;
}
}

As you might have seen already that I’ve specified this class as the target-server property in persistence class.

You can package this class as a part of your application in the same EAR file where you packaged the TopLink Essentials jar files and the entity classes.

Using TopLink 11 with WebLogic 10

If you are using TopLink 11 preview (or EclipseLink) you do not have to create your own server platform class but you can use the server platform shipped in toplink.jar for WebLogic 10.

Here is how your persistence.xml look like when you use TopLink 11.

<persistence-unit name="actionBazaar">
<provider>
oracle.toplink.PersistenceProvider
</provider>
<jta-data-source>
jdbc/ActionBazaarDS</jta-data-source>

<properties>
<property name="toplink.ddl-generation" value="create-tables">
<property name="toplink.ddl-generation.output-mode" value="database">

<property name="toplink.target-server" value="WebLogic_10">

</property>

Note that you have to package toplink-ojdbc.jar in addition to toplink.jar and antlr.jar if you are using Oracle DB as the underlying database.

Hope this helps.
Need to go to bed, feeling sleepy now!

EJB 3 In Action Examples on WebLogic 10

2008-03-23T21:43:00.001-07:00

Several readers requested me to provide the code examples of EJB 3 in Action for BEA WebLogic 10. We have earlier provided examples for Glassfish, Oracle Application Server and JBoss. I spent sometime last weekend to port these examples to Weblogic 10. You can download examples for first four chapters.

These examples have been modified to run on the default examplesServer on the Weblogic in the default server domain. To run the examples, first the set the environment variables by the running the SetExamplesEnv script in $BEA_HOME/wlserver_10.0/samples/domains/wl_server directory.

For example, if you are running on Windows and you have installed WebLogic 10 in C:\bea\wlserver_10.0\ directory you can run the script as follows:

C:\bea\wlserver_10.0\samples\domains\wl_server\SetExamplesEnv.bat

If you unzipped the samples in c:\WLS examples change directory to chapter 1 and you can build and deploy as follows:

cd c:\WLS examples\chapter1

ant - -> attempts to build and deploy in the examplesServer

To run the example:

ant run

You must be wondering what are the changes that I made in the to run on WebLogic 10.

Java EE promises write once run anywhere ! Then why I had to make changes in the code?

Every application server has its minor quirks here and there and code changes were very minimal.

I could not make dependency injection work in the application client code in WebLogic 10, not sure they support it. So I had to change thick client to make use JNDI lookup instead. I modified the Session bean code to define a global JNDI name for the HelloUser session bean as follows: @Stateless(mappedName="HelloUser")

public class HelloUserBean implements HelloUser

I modified the client code to lookup the remote EJB as follows:

Context ctx = new InitialContext(); helloUser = (HelloUser) ctx.lookup("HelloUser#ejb3inaction.example.HelloUser");

As you would expect, I updated the jndi.properties in the client jar file to have right environment properties for WebLogic as follows:

java.naming.factory.initial=weblogic.jndi.WLInitialContextFactory

java.naming.provider.url=t3://localhost:7001
That's it ..

In the next blog entry, I will discuss the code changes the instructions to run Chapter 2-4 and outline changes made to run JPA and MDB examples.

EJB 3.1 New features

2008-01-23T20:40:00.000-08:00

Reza Rehman, my co-author of EJB 3 in Action has authored an article on EJB 3.1 new features.

To summarize the major changes that are planned in EJB 3.1 are:

Singleton Beans. Using a new @Singleton annotation will support
this.
Optional interfaces similar to web services. Container will generate
the interface for you. Anyway IMHO it’s always good practice to build an
interface your bean
Stateful Web services using stateful session beans
EJB
Timers to include cron timers. Just to note that OC4J already supports cron
timer as an extension.

Note that Java Persistence API is now worked under a completely new specification.

You can read the article at http://www.theserverside.com/tt/articles/article.tss?l=NewFeaturesinEJB3-1.

Managing JBoss Application Server from Oracle Enterprise Manager Grid Control

2008-01-07T04:51:00.000-08:00

Although I would like that you use Oracle Application Server always I realize that heterogeneous platforms are reality today :) You may have JBoss application server in your environment and you may want to monitor that from Grid Control. Oracle provides a management plug-in for Grid Control to monitor health and performance of JBoss Application Server.
In this blog entry, I will outline the steps to discover JBoss Application Server from Grid Control.
Let us assume that you have installed JBoss Application Server in a server named dpanda-pc in c:\jboss\jboss4.0.2 directory (call it JBoss_Home), your agent is running on a remote host named dpanda-lap.
1. Login to Grid Control 10g R4
2. Click on Application Servers Menu item
3. Select Add -> JBoss Application Server and click on GO
4. Enter name of the server where JBoss is running as Application Server Host
5. Enter the JBoss Home -> the top level directory where JBoss is installed. Note this is not required if you are using Agent installed on a separate host.
6. You have to supply userid/password only if you have enabled security for JMX Console. See http://wiki.jboss.org/wiki/Wiki.jsp?page=SecureTheJmxConsole how you can make JBoss Console secured. This credential will be used by Agent to make JMX connection to gather health/statistics.
7. You can use a remote Intelligent Agent to discover JBoss. If so you have to appropriately select the check box as depicted in the following figure figure:

The Agent requires the JBoss JMX client jar files to make JMX connection to JMS.

Hence you have to copy the following files to a directory e.g. c:\jboss\lib and make it available to the Agent as Library Path:

jboss-management.jar from JBoss_Home/server//lib

jnp-client.jar from JBoss_Home/client

jbossall-client.jar from JBoss_Home/client

dom4j.jar from JBoss_Home/lib

Note: Make sure that you restart IA otherwise the current status of JBoss Servers will not be reported correctly post discovery.

8. You have to supply the JNDI port for JBoss server and click next

9. Then you have to supply the credentials for the server/host where JBoss is running

10. It will provide a list of the JBoss partitions and/or Servers that it found in the host and you can select the servers that you want to manage and then click Next

After you confirm at the end of wizard , the JBoss servers will be discovered and you can monitor JBoss Application Server from Grid Control.

At Oracle Open World in San Francisco

2007-11-12T05:43:00.000-08:00

Oracle Open World started yesterday. Today I've a session on Java EE with my coworkers Dan Hynes and Dana Singleterry. It is at 3:15pm at Hilton San Francisco. We will present how to build Java EE 5 applications and deploy and manage with Oracle Application Server. If you have a copy of EJB 3 In Action then you can bring it to the session and I can sign it if you want.

I will be hanging around the Oracle Enterprise Manager (Middleware and Apps management booth J04, J06, etc) booths in the demo ground where we are demoing our new product Oracle Application Diagnostics for Java (Oracle AD4J) that help diagnose problems in production environment. Please stop by and learn how Oracle AD4J makes your life simple in diagnosing problems in your production J2EE applications. You can also see some cool demos on SOA management, Application Server Config and Provisioning, SLA management and many more.

Spring and EJB 3: All-Star Team or Neighbors with Good Fences

2007-11-02T01:25:00.000-07:00

I presented a Spring / EJB 3 Comparison/Integration talk at the IndicThreads Java conference in Poona. It was very well received. Here is the link to the presentation for your reading pleasure.

It is primarily based on the contents on our book EJB 3 In Action and my research with my coauthor Reza Rehman on this topic.

All EJB 3 books in the market ignore existence Spring considering it as a competitor. Even the classic Java Persistence on Hibernate says nothing about Spring framework. However EJB 3 In Action takes a pragmatic approach and tries to recommend whenever Spring makes sense. Although Spring and EJB 3 are viewed as competitors it can be used complementary technologies and a whole chapter of EJB 3 In Action is dedicated to this integration story. So why wait .. buy a copy for yourself :)

Using Dependency Injection from Web Container in OC4J 10.1.3.x

2007-10-29T23:02:00.000-07:00

OC4J 10.1.3.1 and later supports dependency injection from web container. I've seen this question from many customers via email or in OTN forum that using dependency injection from web container generates NPE. If you are running into such problems, make sure that you have specified version as "2.5" in your deployment descriptor (web.xml) as follows:

<?xml version = '1.0'?>?
<?web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">?
...

IndicThread Java Conference

2007-09-03T23:29:00.000-07:00

I will be speaking at the IndicThread Java Conference in Pune, India (Oct 26-27). Two of my talks on (Spring / EJB 3 Integration) and SOA management has been accepted. If you are in the Indian subcontinent then it's the only independent Java conference and I highly recommend this conference.

More praises for EJB 3 In Action

2007-07-24T07:34:00.000-07:00

EJB 3 In Action gets Five STARs rating from Cicero Zandoná of JavaLobby.
Here is some excerpt from his review:

If you want an EJB 3.0 book to read from cover-to-cover this is the one. You will learn how to create an EJB application, the concepts related to them and receive a lot of useful advice.
I really can't give this book less then five "stars".

Here is an interesting comment from the book:

One of the authors, Debu Panda is a Lead Product Manager of the Oracle Application Server development team, and I was afraid this could lead to a biased book. Fortunately this doesn't happen at all, he is completely impartial along the book and always warns the reader about vendor-dependent features.

I'm really happy that everyone seems to like the Sadhu story that I started the book with. Here is what Cicero puts in his review:

In an unusual beginning for a technical book, the authors start talking about ladybugs, elephants and cows (one of the authors name is Panda by the way). But I can't think in a more gentle and creative way to illustrate the specification evolution than the analogy they made (you can read the tale in Meera's review).

Read the detailed review at JavaLobby

Automatically Executing a Client Application Archive

2007-07-05T06:01:00.000-07:00

Many applications have a requirement that they want to automatically execute an application client archive(CAR) packaged as a part of enterprise application (EAR) when server starts up or an application is restarted. This is a Java EE 5 standard compliant alternative to Startup class about which I blogged about 2 and half years back!

In this article, I will outline steps to do this in OC4J.

Develop and compile your application client class. This class must contain a main method that will be called by your server during startup.

Create a META-INF/Manifest.mf file for the application-client, for example
Manifest-Version: 1.0
Main-Class: OracleASStartup

Create a deployment descriptor for the application client (application-client.xml) as follows:
<application-client>
<display-name>OracleASStartup</display-name>
</application-client>

Create the application client archive (CAR) file for your startup class with the above Manifest and deployment descriptor.

Create an EAR file for the application client module with the an OC4J-specific deployment descriptor orion-application.xml as follows:
<orion-application>
<client-module path="startup-client.jar" start="true" user="anonymous" >
</orion-application >

Build your EAR and deploy your application with auto start set to "true" as follows in the server.xml:<application name="startup"
path="../applications\startup.ear" parent="default" start="true" >

Whenever your application is deployed or if you restart your server, the application client will be executed automatically!

Hope this helps!

JDJ Article: Java EE 5 and Spring

2007-06-27T07:43:00.000-07:00

JDJ just published second part of my article on Java EE 5/ EJB 3 integration with Spring. You can read the article in the June 2007 issue. Here is link to the article for your reading pleasure.

EJB 3 In Action is #1 spot of hot new released Java Books

2007-06-21T12:47:00.000-07:00

EJB 3 In Action got the #1 spot of best selling new and future release Java books. Note that Amazon keeps on changing the rank every hour

Here is the screen shot that shows that it's #1

IndicThreads Java Coding Contest and EJB 3 In Action

2007-06-06T15:11:00.001-07:00

India's premier Java Developer portal IndicThreads is holding a Java coding contest. This week winner gets a copy of my book EJB 3 In Action!

Also EJB 3 In Action has been reprinted in India by DreamTech press and is available now at most computer book stores!

Injecting POJOs and using resource injection in POJOs

2007-06-04T12:04:00.000-07:00

Java EE 5 greatly simplifies using resources and EJBs by using dependency injection. However this support limits only to managed classes such as EJBs, Interceptors, Servlets, etc. Many applications use helper classes those are regular POJOs. However Java EE 5 / EJB 3 does not require support of dependency injection with regular POJOs or injecting POJOs into managed classes.

In this article, I will discuss about Oracle’s extension of managed POJOs and describes how to use dependency injection such as @Resource or @PersistenceContext with regular POJOs (in OC4J 11 Preview).

This example has a session bean named EmployeeFacade that injects a regular POJO named EmployeeHelper. The EmployeeHelper POJO uses @PersistenceContext to inject an instance of EntityManager.

Using Annotations in regular POJOs

To use dependency injection with regular POJO it does not require any Oracle specific extension. The only requirement is that it must be injected to another managed class by using @oracle.j2ee.annotation.InjectedObject or using Oracle specific descriptor e.g. orion-ejb-jar.xml.

Following is an example of regular POJO that uses dependency injection.

public class EmployeeHelper {
@PersistenceContext
private EntityManager em;
private Employee emp;
public Employee findById(int empNo) {
return ((Employee) em.find(Employee.class, empNo));
}
public Employee saveEmployee(String eName, double sal) {
..
return emp;
}
}

Injecting a POJO
OC4J 11 allows injecting POJOs to a managed class or to another POJO using @oracle.j2ee.annotation.InjectedObject. To inject the EmployeeHelper class into the EmployeeFacade EJB we need the following code:

@Stateless
public class EmployeeFacadeBean implements EmployeeFacade {
@InjectedObject
private EmployeeHelper eh;

public Employee findEmployeeByEmpNo(int empNo) {
return eh.findById(empNo);
}
public int addEmployee(String eName, double sal) {
return eh.saveEmployee(eName,sal).getEmpNo();
}
}

Conclusion

OC4J 11 allows injecting one POJO to another POJO. You can try this with OC4J 11 Preview and let us know what other features you want to see.

Another Five STAR rating for EJB 3 In Action

2007-06-04T09:59:00.000-07:00

Another reviewer of JavaLobby (Michael Smolyak ) gave five star rating to EJB 3 In Action. Here is what he says:

"The book is enjoyable, extremely well organized and covers a wide range of EJB subjects. I would recommend EJB 3 in Action to both old hands and newly-initiated in the EJB craft. My only complaint is the size of the book; but I think the logical, unhurried and deliberate manner, with which the authors approached the non-trivial subjects addressed in this book, making them accessible to EJB novices, and the breadth of material covered in the volume do make up for its weightiness."

Read the detailed review at JavaLobby

JavaRanch gives 9 horseshoes out of 10 to EJB 3 In Action

2007-05-29T10:27:00.000-07:00

EJB 3 In Action gets 9 horseshoes out of 10 from JavaRanch. Read the full review.

EJB 3 In Action is in Amazon's Top 20 Selling Java Books

2007-05-21T13:25:00.000-07:00

A friend of mine send me a note that my book EJB 3 In Action has featured in Top 20 selling Java Book at Amazon.com It was at #18 when I was saw it. Also it was at #10 in the Top Selling Java Books at Amazon Canada.

EJB 3 Action @JavaOne bookstore!

2007-05-10T09:18:00.000-07:00

Few guys told me that their local B & N or Borders do not carry EJB 3 In Action as yet. The Bookstore at JavaOne is selling the EJB 3 In Action. It is offering 20% discount so it's a steal! Also the publisher is offering 35% discount on the book for the JavaOne attendees if ordered from it's website. So get a flyer with a coupon code. Some of these are in the bookstore or around the Oracle's EJB 3/ OC4J booth in the Exhibition Hall!

Using Dependency Injection to invoke EJB deployed in a remote container

2007-05-09T23:45:00.000-07:00

Many applications require invocation of EJBs deployed in a remote container. EJB 3 and Java EE 5 support injection of remote EJB references only in the application client container. Let us say you want to invoke an EJB based on a remote container from your web client (JSF backing bean) or an EJB then you have to resort to the JNDI lookup. Unfortunately injection of remote references have been left as an extension to application server vendors.

In this blog I will demonstrate how OC4J 11g preview supports injection of EJB references that is deployed in a remote container.

Let us assume that we have two Session EJBs HelloWorld and Namaste deployed in two different OC4J instances. The HelloWorld EJB uses dependency injection to get a reference to Namaste EJB located in a remote container.

Stateless Session Bean example using EJB 3.0

We will deploy Namaste EJB into second OC4J instance that will be remotely invoked by the HelloWorld EJB. The following is the coded for the Namaste EJB.

@StatelessDeployment(location="Namaste")

@Stateless

public class NamasteBean implements Namaste

public void sayHello(String name)

System.out.println("Namaste "+name +" from Remote EJB");

Note that the location parameter of @oracle.j2ee.annotation.ejb.StatelessDeployment is used to configure global JNDI name for the Namaste EJB.

Injection Code to Invoke the Remote EJB

OC4J allows injecting remote EJB references (deployed on remotre server) by using a proprietary annotation @oracle.j2ee.annotation.ejb.EJBRefMapping, as shown in the following code. Note that HelloWorld EJB is deployed in OC4J instance 1.

@Stateless

public class HelloWorldBean implements HelloWorld {

@EJBRefMapping(remoteServerRef="true",location="Namaste",

jndiPropertiesFile="META-INF/jndi.properties")

@EJB

private Namaste namaste;

public void sayHello(String name) {

System.out.println("Hello " + name+ " from your first EJB 3.0 component ... ");

System.out.println("Using Injection to invoke method of Namaste Bean! See console of remote container ");

namaste.sayNamaste(name);

}

The location element specifies the global JNDI for the remote interface of the EJB and jndiProperties file specifies the JNDI properties such as provider URL, principal, credential, etc to look up the remote EJB as follows:

java.naming.factory.initial=oracle.j2ee.rmi.RMIInitialContextFactory
java.naming.provider.url=ormi://localhost:23792/remoteDI
java.naming.security.principal=oc4jadmin
java.naming.security.credentials=welcome

You can use @EJBRefMapping annotation in any manage classes in the container such as Servlet, listeners or managed POJOs. If you are not comfortable using Oracle's extension, you can use the equivalent in oracle-ejb-jar.xml.

Client Code

The client code runs in Oracle’s application client container and uses dependency injection to invoke methods on HelloWorld EJB as follows:.

public class HelloWorldClient {

@EJB

private static HelloWorld helloWorld;

…

helloWorld.sayHello(name);

}

Conclusion

Dependency Injection of remote EJB references in not standardized. You can use Oracle's proprietary extension to injection remote EJB references.

Should EJB 3 contain support for EJB 2? Yes, ALWAYS !!

2007-05-09T11:32:00.000-07:00

I read the interesting blog by Andreas where he makes argument that EJB 2 should have been optional in EJB 3!

In my opinion, “No, never”. There have been countless EJB 2 applications in production and I still see many developers actively developing/deploying EJB 2 applications because many application servers such as IBM Websphere still do not have support for EJB 3 in their production servers. Many of EJB 2 applications will migrate to use EJB 3 but many will probably hang around for years. Support for EJB 2 and EJB 3 together allows applications to interoperate between applications using two different versions of applications deployed in the same container. This also enables customers to do a phased migration of applications. Having said that EJB 3 de-supported EJB 1.1 and I still want to see support for EJB 2.1 in EJB 3.1. I think it makes sense for a standard to support at least two earlier releases. I’m okay if EJB 4 (probably it will at least 2-3 years from now) de-supports EJB 2.1. If Sun decides to EJB 2.1 in EJB 3.1 then most customers will probably be mad and decide to dump EJB :) Anyway vendors like Oracle will keep supporting EJB 2.1 with EJB 3.1 to keep their customers up and running!

Oracle releases Java EE 5 compatible container!

2007-05-08T15:18:00.000-07:00

Oracle released Java EE 5 compliant Oracle Application Server 11 technology preview. This preview has several extensions to the Java EE 5 that includes the POJO injection, injection remote EJB references, embeddable Spring container and many more. I'm at JavaOne currently and I will blog about these features in coming days!

EJB 3 In Action: Book Signing

2007-05-03T11:17:00.000-07:00

I will do a book-signing at JavaOne next week. You can drop by at the DigitalGuru Bookstores at Moscone between 4:00-4:30pm on Tuesday(8th May) with your copy of the EJB 3 In Action or buy one at the bookstore and get it autographed!

See you at San Francisco and have a great JavaOne!

JDJ Article: Spring and Java EE 5

2007-04-26T13:05:00.000-07:00

JDJ published part-1 of my article Spring and Java: Simplicity and Power Combined in their latest issue. In the first part of article I discuss the Simplicity brought by Java EE 5 and integration between Spring and JPA. Stay tuned for the second part of the article in which you will discover how the Spring Framework integrates with other components such as an EJB, Java Message Service (JMS), and transaction manager.

Amazon finally started shipping!

2007-04-23T16:48:00.000-07:00

I got few queries from readers about Amazon.com giving a shipping date in mid-May for my book EJB 3 In Action. I had put a test order and Amazon.com notified I that they shipped the order. Both Amazon.com and Amazon UK have started shipping. Amazon Canada still shows pre-order. I think it is now available in bookstores such as Barnes and Noble and Borders by now!

Google Alert Works sometime: Great Review from JavaLobby!

2007-04-12T05:49:00.000-07:00

Google's alert works sometimes! I've an alert set for "EJB 3 In Action" and I mostly ignore because mostly I get alerts for web pages that were created couple of years back. But it was an early morning suprise. We have a great review from DZone / JavaLobby. We have got five smileys (the highest) in all respects: relevance, readability and overall. It was good to know that the reviewer (Meera) had reviewed two other EJB 3 books (O'Reilly and Apress) earlier and she gives us highest marks!

Here is her concluding remark:

"When you start reading a technical book within the first few pages itself you really know whether you like the book or not. This book was very interesting to me and kept the interest all the way until the end. I found this book to be well worth the time I spent reading it in spite of me being quite familiar with EJB3 as well as JPA. If you are planning on using EJB3 or even migrating your existing EJB 2 applications, I would highly recommend this book.

Last but not the least, Part 4 and Part 5 of this book, and the performance considerations and best practices for EJB's at the end of a few chapters in itself is worth the price of the book."

Take a look at the complete review!

My Copies of EJB 3 In Action Arrived

2007-04-11T08:00:00.000-07:00

My copies of EJB 3 In Action arrived yesterday. I've been waiting and waiting because the binders shipped those on 4th. And it was misdelivered to at my neighbor's door by UPS a couple of days ago!

Anyway here is a picture of the book after I opened!

Article:Packaging EJB 3 Applications

2007-04-10T14:40:00.000-07:00

Developer.com published an article Packaging EJB 3 Applications that is an excerpt from the Chapter 11 of our book EJB 3 In Action!

This article provides:
1. Overview of Java EE packages such as EAR, WAR
2. An intro to Classloading and classloading in Java EE
3. Packaging Session beans and MDBs
4. Discussion on annotations and overriding with descriptors

EJB 3 In Action Now available!

2007-04-06T13:02:00.000-07:00

Print copies of EJB 3 In Action have left the printers and are now available. It will take about 10 days-to 2 weeks for Amazon and book stores to stock up and start shipping. The fastest way to get your print copy is to order at the publisher's web site http://www.manning.com/panda/!

Oracle Acquires Tangosol

2007-03-23T10:30:00.000-07:00

Oracle announced that it will acquire Tangosol. Congrats Cameron and gang and welcome to Oracle!

Using @EJB annotation across different ejb-jar module

2007-03-21T13:12:00.000-07:00

I got some questions from customers on how to use @EJB annotation to inject instance of a session packaged in another EJB-JAR. In this blog entry I will outline how to do that.

Let us assume that you have two stateless beans SessionEJB1 and SessionEJB2 and those are packaged in two different EJB modules ejb1-ejb.jar and ejb2-ejb.jar respectively. You want to use inject SessionEJB2 (in ejb2-ejb.jar) from SessionEJB1 (packaged in ejb1-ejb.jar) then you can just do the following:

@Stateless
public class SessionEJB1Bean implements SessionEJB1, SessionEJB1Local {
@EJB
testejb2.SessionEJB2 ejb2;

This works great in OC4J 10.1.3.1.

Optionally you may do as follows, following the ejb-link convention that we used in EJB 2.

@EJB(beanName="ejb2-ejb.jar#SessionEJB2Bean",
beanInterface=testejb2.SessionEJB2.class)
testejb2.SessionEJB2 ejb2;

I've seen this problem when I deploy from JDeveloper. If you are using JDeveloper 10.1.3.1 and getting NameNotFoundException then make sure that your dependent ejb-jar module does package duplicate classes. By default when you declare a dependency on another project the classes are automatically packaged in the dependent jar e.g. ejb1-ejb.jar in our case. You have to verify it using the deployment profile for your EJB module. Make sure that you have unchecked the classes by selecting filters.

Hope this works for you!

EJB 3 In Action goes to press: eBook now available!

2007-03-20T09:39:00.000-07:00

EJB 3 In Action went to press late last week. The e-Book has been published at the Manning web site . Print copies of the book will be available at Manning web site for order and hit the shelves at the brick and mortar stores such as Barnes and Noble and Borders in another 2-3 weeks.

Two sample chapters (chapter 1 and 11) are available free at the book site. You can take a look at the preface, table of contents and index.

You can order the book from Amazon.com at http://www.amazon.com/Ejb-3-Action-Debu-Panda/dp/1933988347

The global sites at Amazon screwed up the listing and show two books. It was due to the change in ISBN. Note the correct ISBN is: 1-933988-34-7 and book is of 700 pages.

Here are links to the correct book at Amazon sites for few countries

Canada : http://www.amazon.ca/Ejb-3-Action-Debu-Panda/dp/1933988347

France : http://www.amazon.fr/Ejb-3-Action-Debu-Panda/dp/1933988347

Germany: http://www.amazon.de/Ejb-3-Action-Debu-Panda/dp/1933988347

Japan: http://www.amazon.jp/Ejb-3-Action-Debu-Panda/dp/1933988347

UK : http://www.amazon.co.uk/Ejb-3-Action-Debu-Panda/dp/1933988347

With the release of the book I’m relieved and looking forward to reviews by readers. We have a great draft review from JavaRanch and hope many good reviews will pour in!

EJB 3 In Action: Book Promotion

2007-03-13T08:22:00.000-07:00

JavaRanch has arranged a promotional event for our book EJB 3 In Action (http://www.manning.com/panda/) . You can ask some questions about our book or EJB 3 technology in general in their EJB and Technologies forum and get a chance to win a copy of the book.

The book goes to press today. eBook will be available on Mar 15 and print copies will be available Mar 30. You can buy eBoook or print book from Manning web site.

You can also order copies from Amazon!

EclipseLink FAQ

2007-03-06T14:34:00.000-08:00

Oracle proposed the EclipseLink Persistence framework based on its TopLink product. I forgot to link the FAQ for this. Here it is !

Oracle open sourced complete TopLink product as an Eclipse project

2007-03-06T10:39:00.000-08:00

Oracle donates the complete TopLink product to Eclipse.

You may remember that Oracle had earlier contributed TopLink Essentials (a part of TopLink) to Sun’s Glassfish project that became the reference implementation for the EJB 3 JPA spec. However today's announcement is for proposing new Java persistence project based on TopLink product that includes support for ORM, Object-XML Mapping, JAXB, SDO, etc.

See the complete press release

Customizing JNDI name for Session beans

2007-03-02T09:50:00.000-08:00

Every vendor provides its own way of registering Session bean interfaces into their global JNDI tree. If you care about portability then you should NOT depend upon the global JNDI name and use the ref-name by using ejb-ref or ejb-local-ref and lookup the EJB from environment naming context using java:comp/env/<ref-name>. However many have their own reasons not to use the standard convention and use the vendor specific JNDI name.

If you are such a soul and want to customize the global JNDI name for a session bean in OC4J you can package an orion-ejb-jar.xml and specify location attribute (for remote interface) and local-location (for local interface) as follows:

<session-deployment location="PlaceOrderBean" name="PlaceOrder"></SESSION-DEPLOYMENT>

Note that OC4J uses the ejb-name element in the ejb-jar.xml or name parameter in @Stateless or @Stateful annotations as the default JNDI name for the remote interface.

If you are using EJB 3 and annotation fanatic then you can use either @StatelessDeployment or @StatefulDeployment annotation to specify the JNDI names as follows:

@StatefulDeployment(location="PlaceOrder",
localLocation="PlaceOrderBeanLocal")

Even if I want you to marry to our platform and use the global JNDI name so that your migration becomes difficult but I will advise against using global JNDI names and recommend that you to use ejb-ref for portability reasons.

OC4J Connection Pooling and non-Oracle databases

2007-02-19T10:22:00.000-08:00

In my last entry I blogged about using MySql database with OC4J. I provided an example of native datasource that connects to the MySql database. Native data sources do not use connection pooling capabilities of OC4J. If you want use OC4J connection pooling with third-party databases you have to use a managed data source.

Here is an example managed data source for MySql database.

<connection-pool name="test Connection Pool">

factory-class="com.mysql.jdbc.jdbc2.optional.MysqlDataSource"

user="user1"
password="user1"
url="jdbc:mysql://144.25.134.24/Test">
</CONNECTION-FACTORY>
</CONNECTION-POOL>

<managed-data-source>
connection-pool-name="test Connection Pool"
jndi-name="jdbc/mysql"
name="mysql"/>

You have to make sure that the factory-class in the connection-factory tag points to the DataSource class for your your database.

Using MySQL with OC4J 10.1.3.x

2007-02-14T10:54:00.000-08:00

When you have OracleXE available for free you would probably not use MySQL, but you may have a valid requirement to use MySQL with OC4J 10.1.3.

1. Upload JDBC Driver You have to make JDBC drivers (e.g. mysql-connector-java-3.0.11-stable-bin.jar) for your database available to Oracle Application Server. You have to copy those to %ORACLE_HOME%/j2ee/home/applib directory.

2. Create a Native DataSource

You can use the ASC to create a native data source as follows:

jndi-name="jdbc/MyDS"
description="Native DataSource" data-source-class="com.mysql.jdbc.jdbc2.optional.MysqlDataSource"
user="user"
password="password"
url="jdbc:mysql://localhost:3306/mydatabase">

Now you should be able to access the DataSource connecting to MySQL database with a JNDI location "jdbc/MyDS".

EJB 3 In Action Book Update

2007-02-07T13:06:00.000-08:00

Here is an update for book EJB 3 In Action. We are done writing and editing and going thru final round of proof reading before getting published. The book will be published next month. The eBook will be available first week of March and print book will be available Mar 15.

You can purchase and read the final draft of the book using Manning's MEAP program or pre-order from Amazon .

If you have any questions about the book or found any technical errors please report to the Author forum

Here is Table of contents of the book:

1. What's what in EJB
2. A First taste of EJB
3. Building Business Logic with Session beans
4. Messaging and Developing Message Driven Beans
5. Learning Advanced EJB Concepts
6. Transactions and Security
7. Implementing Domain Models with EJB 3
8. Object-Relationship Mapping using EJB 3 JPA
9. Manipulating entities with EntityManager API
10. Using the Query API and the Java Persistence Query Language
11. Packaging EJB 3 Applications
12. Effectively Integrating EJB 3 across Your Application Tiers
13. Taming Wild EJBs: Performance and Scalability
14. Migrating to EJB 3
15. Exposing EJBs as Web Services
16. EJB 3 and Spring

Appendix A. RMI and JNDI
Appendix B. Reviewing relational databases
Appendix C. Annotations reference
Appendix D. Deployment descriptors reference
Appendix E. Installing and configuring the Java EE 5 SDK

Using Hibernate as a Pluggable EJB 3 JPA Provider

2007-01-30T14:28:00.000-08:00

EJB 3 supports pluggable persistence contract that allows you to plug-in any persistence provider implementing JPA 1.0 with a container that supports JavaEE 5 / EJB 3 spec. It’s provides choice to users to choose their JPA provider of choice. I thought I would give a spin and check whether this plug-ability story really works and here is the result!

I used Oracle Application Server 10g 10.1.3.1 that has support for EJB 3.0 spec (not yet EJB 3 / Java EE 5 compliant) and Hibernate 3.2 that is JPA 1.0 compliant to see whether the plug ability story is real! Oracle Application Server by default uses TopLink Essentials as the JPA provider. Note that TopLink Essentials is the Reference Implementation for the JPA spec.

Loading the Hibernate Libraries in the server

In order to use Hibernate as a pluggable persistence provider, you have to make sure that Hibernate Entity Manager and related libraries are made available to the container class path.

I created a shared library in OC4J named Hibernate and uploaded the required jars. Following is the definition of the shared library:

<shared-library name="Hibernate" version="3.2">
<code-source path="hibernate-entitymanager.jar"/>
<code-source path="hibernate3.jar"/>
<code-source path="jboss-archive-browsing.jar"/>
<code-source path="dom4j-1.6.1.jar"/>
<code-source path="hibernate-annotations.jar"/>
<code-source path="javassist.jar"/>
<code-source path="commons-collections-2.1.1.jar"/>
<code-source path="ehcache-1.2.3.jar"/>
<code-source path="c3p0-0.9.1.jar"/>
<code-source path="concurrent-1.3.2.jar"/>
<code-source path="cglib-2.1.3.jar"/>
<code-source path="asm.jar"/>
<code-source path="asm-attrs.jar"/>
<code-source path="antlr-2.7.6.jar"/>
<code-source path="commons-logging-1.0.4.jar"/>
<code-source path="log4j-1.2.11.jar"/>
</shared-library>

Make sure that application imports the shared library. You can do so by either importing the library during deployment or packaging an orion-application.xml as follows:

<orion-application xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlns.oracle.com/oracleas/schema/orion-application-10_0.xsd" deployment-version="10.1.3.1.0" default-data-source="jdbc/OracleDS" component-classification="external"
schema-major-version="10" schema-minor-version="0" >
<imported-shared-libraries>
<import-shared-library name="Hibernate"/>
</imported-shared-libraries>
</orion-application>

Configuring the Persistence Unit

You need to configure the persistence unit to specify the persistence provider and other vendor specific properties in the persistence.xml. For my test application I created a simple entity class and packaged the following persistence.xml in my application that uses Hibernate 3.2 as the JPA provider.

<persistence>
<persistence-unit name="howto">
<jta-data-source>jdbc/OracleDS</jta-data-source>
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.OC4JTransactionManagerLookup"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.OracleDialect" />
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
<property name="hibernate.show_sql" value="true" />

</properties>
</persistence-unit>
</persistence>

Note that in above I set provider class to org.hibernate.ejb.HibernatePersistence that tells the container to use Hibernate 3.2 as the persistence provider instead of using TopLink Essentials as the JPA provider.

Access to Transaction Manager

The primary reason behind the pluggable persistence provider is to provide facility to use JPA with a container managed Entity Manager and hence Hibernate needs to access the JTA Transaction Manager of the container.

Hibernate 3.2 does not use the JTA TransactionSynchronizationRegistry whose sole purpose is for such integration.

Instead it provides classes for each application server that looks up the Transaction Manager.
For example,org.hibernate.transaction.OC4JtransactionManagerLookup is provided with Hibernate as a persistence property to lookup OC4J’s transaction manager as follows:

<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.OC4JTransactionManagerLookup"/>

If you want to use another application server then you have to the class for that server.

Deploy and Run Your Application

You can package your entities and then deploy to the server

Now after you deploy your application into OC4J you should be able to run your application. If you used the property hibernate.show_sql to true, you will see similar output from Hibernate in your console.

07/01/30 12:11:54 Hibernate: insert into EMP (ename, sal, EMPNO) values (?, ?, ?
)
07/01/30 12:11:55 Hibernate: select employee0_.EMPNO as EMPNO0_0_, employee0_.en
ame as ename0_0_, employee0_.sal as sal0_0_ from EMP employee0_ where employee0_

Conclusion

I did some testing and the application works as expected and hence I conclude EJB 3 delivers on the plug-ability story and Oracle Application Server 10g is Hot Pluggable!

Using global-jndi-lookup-enable to lookup EJBs across applications

2007-01-22T12:15:00.000-08:00

OC4J 10.1.3.1 allows lookup of EJBs across application by enabling the global JNDI lookup.

To use the global JNDI feature in OC4J, first you have to enable it.
1. Using a text editor, open config/server.xml.
2. Within the <application-server> element, add the global-jndi-lookup-enabled attribute and set it to true as follows:

<application-server global-jndi-lookup-enabled="true">
</application-server>

3. Save and close server.xml.

4. Restart the application server.

5. Deploy application that contains the EJB. Let us say the application name is APP2 that contains a remote EJB with JNDI location “EmployeeFacadeBean”.

To find the JNDI location look at the generated orion-ejb-jar.xml in the server’s application deployment directory. To configure a different JNDI location package an orion-ejb-jar.xml as follows:

<session-deployment name="EmployeeFacadeBean">
name="EmployeeFacadeBean" location="EmployeeFacadeBean"

</session-deployment >

The default JNDI name is the name of the remote interface of the session bean configured using the ejb-name element in ejb-jar.xml or name element of @Stateless or @Stateful annotations.

The client application that looks up the EJB must package the remote, home, interfaces to look up the remote EJB.

You can lookup the EJB from the client application using the JNDI location as follows:

Context ctx = new InitialContext();
employeeFacade = (EmployeeFacade) ctx.lookup("EmployeeFacadeBean");

Now you deploy your client application and the application should be able to lookup the EJB in APP2!

If you want to use in OC4J 10.1.3.0.0 then make sure that you apply 10.1.3.1 patchset!

EJB 3 In Action: Code Samples

2007-01-18T22:01:00.000-08:00

The code samples of EJB 3 In Action are now available from the Manning web site. We have made the source code available for Java EE SDK (Glassfish) and Oracle Application Server. You can download the code samples from the book site. All chapters of the book are available at the book site through the Manning's MEAP program. So ahead an pre-order a copy for yourself and read the final drafts of the book from the Manning site

Blogger ATOM Woes and RSS URL for blogger !

2007-01-08T11:07:00.000-08:00

My transition to Blogger has been smooth except few hiccups. Few weeks back Blogger switched to ATOM 1.0 by default and many blog aggregators that do not support ATOM yet (such as Javablogs.com) stopped taking updates from my Blog. After a lot of research I found that Blogger provides an URL with RSS 2.0 feeds. For example you can get RSS 2.0 feed for my blog at http://debupanda.blogspot.com/feeds/posts/default?alt=rss

Happy New Year!!

2007-01-08T10:55:00.000-08:00

Wish you a very happy and prosperous 2007! Now that I’m back from 5 weeks trip to India and back from jet lag. Ready to Blog, Stay Tuned!

@IndictThreads Java Conference

2006-12-01T22:57:00.000-08:00

I've been traveling in India for about 10 days now. Now I'm in Poona attending the IndicThreads Java conference. Great work by Harshad Oak and his crew in arranging such a Java conference in India. I spoke yesterday and my session was tittled EJB 3 in Action and it was a house full. I will have a Q & A session along with Gavin King on EJB3 / JPA later today.

Spring/EJB 3 HowTos/Code Examples

2006-11-07T10:37:00.000-08:00

I built couple of howtos for using Spring 2.0 with EJB 3/JPA and these have been referenced from Spring's home page.

How To: Using EJB 3.0 Session Beans with Spring Beans : Zip with Code examples In OTN

How To Use EJB 3.0 and Java Persistence API with Spring : Zip with Code examples In OTN

Please note that this works with Oracle Application Server 10g 10.1.3.1

These samples also work with Glassfish by tweaking the packaging a little bit. You have to just make sure that you modify the packaging to include Commons Logging jars required by Spring. If you want the build script for Glassfish please drop me an email and I will send that to you.

My Book @ Amazon.com

2006-11-02T09:16:00.000-08:00

Finally my book EJB 3 In Action is available at Amazon.com for pre-order. The book has already been available for purchase under Manning's MEAP program that provides ability to read pre-production version of the book today!

Pre-order at Amazon

Pre-order and MEAP at publisher's website

EJB 3 Extensions in Oracle Application Server 10g 10.1.3.1

2006-11-01T11:59:00.000-08:00

Oracle has built some extensions to its EJB 3 implementation in Oracle Application Server 10.1.3.1 to simplify developers' life. In this blog I will uncover these extensions.

Vendor Specific Annotations

We have added three proprietary annotations @StatelessDeployment, @StatefulDeployment and @MessageDrivenDeployment that you can use to specify Oracle specific configurations for your bean. This frees you from having to deal with vendor specific descriptor. For example, you can use the @StatelessDeployment annotation to specify pooling information for an EJB as follows:

import oracle.j2ee.ejb.StatelessDeployment;

@StatelessDeployment(minInstances = 100, maxInstances = 500)
@Stateless
public class HelloBean implements Hello {
..
}

Additionally we have provided annotations to be used with EJB 3 web services (that use web services metadata annotations) : @Deployment, @Schema, @WSIFEJBBinding, etc. The @Deployment annotation is most important annotation of these and can be used to specify portName, contextPath or expose the web service as a REST web service.

For example:

@Deployment(contextPath="ejb30", uriPath="ejb30-simple", portName="MyWebService")
@WebService
@Statelesspublic class HelloBean{
..
}

You can refer to the Oracle Annotations Java Doc for details about these annotations.

Simplification to Use JPA inside container

We have added several small knobs here and there to simplify use of JPA inside container.

persistence.xml is optional in EJB Modules

JPA requires persistence.xml for configuring a persistence unit. This is really a headache for developers when using entities in an EJB module and has only one persistence unit. Oracle Application Server makes it optional and will search for entities in the ejb-jar and configure a default persistence unit for you. The data-source will be defaulted to the default data source configured for the application or server. This will also help customers using EJB 3 in OracleAS 10.1.3.0 to migrate to OracleAS 10.1.3.1 easily.

Using @Resource annotationInjecting container-managed EntityManager

Many developers have asked why can’t they use @Resource annotation to inject a container managed EntityManager? It seems really odd that you can inject other resources such as DataSource but not EntityManager. The real answer is EntityManager is not a resource and you may have more than one persistence unit. If you have only one persistence unit in your application OracleAS has extension to support injection of EntityManager using @Resource as follows:
@Resource EntityManager em;

This also helps customer to migrate their applications to OracleAS 10.1.3.1 from earlier release.

persistence.xml in WEB-INF

If you have used entities in the web module then you know that Java EE 5 requires packaging of persistence.xml in the WEB-INF/classes/META-INF directory. It is really confusing for developers because all descriptors for web module are placed in WEB-INF directory. Why not persistence.xml you may ask? There is a real reason (and there was hot discussion in the EJB3 expert group) for this that I will discuss in a future blog. However it is worth mentioning here that OracleAS makes it simple and allow packaging of persistence.xml in WEB-INF/ directory and if found it will be considered to similar to packaging it in WEB-INF/classes/META-INF directory.

Hope these extensions make your life easier. If you have an idea for a feature that you would like to see in OracleAS do not hesitate to send that to me.

Is BEA far ahead in Java EE 5 game?

2006-10-26T23:41:00.000-07:00

It was interesting to read this article in Dr Dobb's Java portal (and InfoQ' s thread ) that noted that BEA is ahead of others in the Java EE 5 game. In my personal opinion (note that this blog is my personal opinion and nothing to do with my employer's), these are really biased articles and reflects the mindset of the writer "BEA is always ahead!"

As per the article EJB 3/JPA covers significant portions of Java EE 5 and hence the reality shows otherwise. Oracle and JBoss had EJB 3 previews for years (yes years, we released our first EJB 3 preview in early March 2005, See my announcement) and both JBoss and Oracle have production release of EJB 3/JPA in their application server. Look for complete EJB 3/ JPA support in Oracle Application Server 10g 10.1.3.1 whereas BEA just has tech preview of a subset of EJB 3 specification. They have support for Java Persistence API in Kodo but the article in DDJ also acknowledges Kodo is not yet integrated with the WebLogic and hence you cannot use its full power. However Oracle’s JPA implementation TopLink Essentials is totally integrated with Oracle's Java EE container (OC4J) and is also shipped with Glassfish, TmaxSoft and popular Spring 2.0!.

Beside full implementation of EJB 3 and JPA, Oracle has also support for Web services metadata, annotations support in the Servlet (2.5) and application client container in Oracle Application Server (10.1.3.1). Above all these features work in a truly integrated fashion that customers can use in production today. You cannot use JSR-181 annotations with an EJB 3 session bean in a production environment with WebLogic but can do that today with OracleAS !

Try running a complicated application such as Java Adventure Builder that uses EJB 3 /JPA / Web services metadata in the WebLogic Tech Preview. If you can’t do these things then what made the author to assume that BEA is ahead of JBoss and Oracle in the Java EE 5 game.

It truly frustrates me when seeing such biased articles because many gullible readers treat such articles as bible.

Many Oracle customers have started deploying EJB 3.0/JPA applications in production. Can you do that with BEA? If not then how can you say that they are ahead in the game!

EJB 3 In Action: What's what in EJB 3

2006-10-26T12:31:00.000-07:00

Manning has made available 9 chapters of EJB 3 In Action as part of MEAP Release. Draft version of chapter 1 “What’s what in EJB 3" is available for free. Take a look at this at http://manning.com/panda/.

You will probably like the beginning story of an Indian boy named Sadhu and it's comparison with EJB’s incarnations. You can access the chapter at http://manning.com/panda/.

Java annotations support in the web container

2006-10-25T23:44:00.000-07:00

Servlet 2.5 (a part of Java EE 5) provides support for Java metadata annotations. You can use annotations for callback methods, security, injection of resources, EJB and web service reference, EntityManager, etc.

You can also package a persistence module (EJB3 JPA entities) as a part of a WAR module.

Injection of Resources

You can use the @Resource annotation to inject resource references such as Data Source e.g. you can inject a Data Source as follows:

@Resource(name="jdbc/OracleDS")
private DataSource dataSource;

CallBack Methods

You can use @PostConstruct and @PreDestroy annotations with any arbitrary method to behave like init() and destroy() methods respectively. For example you can have a method named openConnection that opens a connection as follows:

@PostConstruct
public void openConnection() {
try {
connection = dataSource.getConnection();
} catch (SQLException sqle) {
sqle.printStackTrace();
}
}

Things to Remember

Note that annotations are supported only with managed classes such as servlet, filters, listeners, etc. You cannot use annotations with regular POJOs.

You have to make sure that you have set version=”2.5” in the web.xml for the web-app tag as follows: ...

...

If you have set that to a lower version or not set then container will not search for annotations and you will probably get a NullPointerException at run time when trying to use a field assuming it’s value to populated using injection.

OC4J 10.1.3.1 supports all Servlet 2.5 annotations that includes @EJB, @Resource, @Resources, @PostConstruct, @PreDestroy, @PersistenceUnit(s), @PersistenceContext(s), @WebServiceRef, @DeclaresRoles, @RunAs.

It also allows packaging of EJB 3/JPA entities in the web module.

Missing annotations ..!

I think one think that is missing is that there are annotations to specify a type of an object similar to @Stateless annotation in EJB 3.0.

For example, you CANNOT mark a POJO to be a servlet as follows:
@Servlet
public class MyServlet
{ …
}

I would like to see annotations such as @Servlet or @Filter in future version of Servlet specification.

More Info

You can find more about Servlet annotations in Servlet 2.5 spec or OC4J 10.1.3.1 documentation.

Oracle Application Server 10.1.3.1 Goes Production

2006-10-20T08:55:00.001-07:00

Oracle announced production release of Oracle Application Server10g 10.1.3.1. This release of OC4J implements significant features of Java EE 5.0 that includes full implementation EJB 3.0, JPA 1.0, Common Metadata annotations 1.0, Servlet 2.5 annotations, annotations support in the Application Client Container support and web services metadata.

You can download from OC4J home page at http://www.oracle.com/technology/tech/java/oc4j/index.html

Oracle Application Server 10.1.3.1 Goes Production

2006-10-20T08:55:00.000-07:00

Early Access Edition of EJB 3 In Action

2006-10-13T09:19:00.000-07:00

I participated in several beta and early access testing of products, reviewed books but never participated in an Early Access Program for a book. And certainly Manning Early Access Program sounds interesting.

An early release version of my book EJB 3 Action is now available at http://manning.com/panda/

It's a little better form of pre-ordering from Amazon or a publisher web site. You immediately get access to the source or final pre-production version of the book online and Manning Publications will ship you a book as soon as book is published. In the mean time you are the beta testers of the book (:

I will appreciate you participate in this program, pre-order a copy and help find any errors in the book (:

JavaZone @Oslo!

2006-09-20T10:24:00.000-07:00

My trip to Oslo was very nice. The weather was pretty good there. It was my first talk at JavaZone. It is really a nice Java conference. It's certainly better, bigger than the conferences like TheServerSide symposium. About 1400 people attended.

All familiar conference presenters Rod Johnson, Joshua Bloch, Floyd, Patrick Linskey, etc were presenting there.

One thing that I liked about the conference that there it was free from keynote. My presentation Migration to EJB3 was houseful! You can download my presentation from JavaZone website.

My upcoming talks at JavaZone and OracleDevelop

2006-09-07T17:07:00.000-07:00

I’ll be presenting in JavaZone, Norway next week. Hope to see you if you are attending the conference. I will deliver a presentation on Oracle Develop conference held Oct 23-25. . This conference is primarily for developers using Oracle platform and there will be many talks for developers. There are many great speakers including Rod Johnson who will present in the Oracle Develop conference.

Hope to see you in one of these conferences!

Using EJB 3.0 Message Driven Bean with JCA-Resource Adapters

2006-08-24T11:40:00.000-07:00

MDB was the only bean type that did not suffer obesity problems with EJB 2.x. It was simple to develop and use and it was liked by most developers.

For many developers the verbose XML descriptor was still a sour-point. EJB 3.0 further simplified message driven bean by removing the requirement to use descriptors and you can use annotations to specify the activation config properties.

An Example MDB with EJB 3.0 Annotations

A simple MDB will look like as follows:

@MessageDriven(activationConfig = {
@ActivationConfigProperty(propertyName = "ConnectionFactoryJndiName", propertyValue = "jms/TopicConnectionfactory"),
@ActivationConfigProperty(propertyName = "DestinationName", propertyValue = "jms/demoTopic"),
@ActivationConfigProperty(propertyName = "DestinationType", propertyValue = "javax.jms.Topic"),
@ActivationConfigProperty(propertyName = "messageSelector", propertyValue = "RECIPIENT = 'MDB'")
})
public class MessageLogger implements MessageListener{..}

This problem with MDB is that it works will the default JMS provider of the container i.e . in-memory JMS provider of OracleAS.

Using MDB with a JCA-compliant Resource Adapter

There are many instances probably you want to use a messaging provider (JMS or non-JMS) plugged-in using a JCA-compliant connector or resource adapter. Let us assume that OracleAS JMS wit the global connector (named OracleASjms) packaged with Oracle AS. Unfortunately EJB or JCA does not standardize configurations for using a resource adapter and you have to depend upon a proprietary feature such as vendor specific annotation or activation config property to designate the resource adapter to be used with your MDB. Oracle provides a vendor specific annotation (@oracle.j2ee.ejb.MessageDrivenDeployment) to specify Oracle specific configuration properties and you need to use resourceAdapter element to specify the resource adapter that you intend to use. For example you can modify the above MDB as follows to use the OracleASjms global connector to use the In-memory JMS as follows:

@oracle.j2ee.ejb.MessageDrivenDeployment(resourceAdapter="OracleASjms")@MessageDriven(activationConfig = {
@ActivationConfigProperty(propertyName = "ConnectionFactoryJndiName", propertyValue = "OracleASjms/MyTCF"),
@ActivationConfigProperty(propertyName = "DestinationName", propertyValue = "jms/demoTopic"),
@ActivationConfigProperty(propertyName = "DestinationType", propertyValue = "javax.jms.Topic"),
@ActivationConfigProperty(propertyName = "messageSelector", propertyValue = "RECIPIENT = 'MDB'")
})
public class MessageLogger implements MessageListener {.}

Note that we have modified the ConnectionFactoryJndiName to use a pre-configured connection factory OracleASjms/MyTCF.

Using a non-JMS Connector

Let us assume that you want to use your own non-JMS resource adapter let us say thirdra then your EJB 3.0 MDB will look as follows:

import oracle.j2ee.ejb.MessageDrivenDeployment;
import thirdra.common.ThirdListener;
@MessageDriven(name="thirdmdb",messageListenerInterface=ThirdListener.class)@MessageDrivenDeployment(resourceAdapter="thirdra")
public class MessageLogger

Isn’t is simpler than EJB 2.x where you had to handle at least two XML descriptors? If you want to use mix-n-match with descriptor (ejb-jar.xml) make sure that version is set to "3.0" in your ejb-jar element otherwise annotations will not be parsed and container will treat it as an EJB 2.1 descriptor.

However I strongly feel that specifying a resource adapter should be standardized by the future release of specification.

Top 5 features you would care about in OC4J 10.1.3.1!

2006-08-17T00:28:00.000-07:00

OC4J 10.1.3.1 Developer Preview was released couple of days back. OC4J 10.1.3.0 was released in January that had a truckload of features. A question that might comes to your mind: Is OC4J 10.1.3.1 a patch release? From Java developer’s perspective OC4J 10.1.3.1 may not be feature-rich like OC4J 10.1.3.0. However it has a lot of features that you might care about.

1. It now has complete implementation of EJB 3.0/JPA final specifications. It means you will see several changes in the EJB container, that includes:

EJB 3.0 Persistence now fully aligns with the spec.
Lifecycle listeners and Interceptors are aligned with the spec.
XML descriptors support is aligned with the spec.

See the updated demos at EJB 3.0 Resource Center.

2. We have added Oracle specific annotations for easier configurations. If you hate descriptors you have an option to make EJB configurations without having to use orion-ejb-jar.xml. Additionally we have added many proprietary enhancements to make usage of EJB 3.0 simpler. We have made persistence.xml optional in an ejb-jar module for packaging entities and use @Resource to inject the EntityManager for the default persistence unit. I will blog about these later.

3. Dependency injection is supported in the application client container and web container. You can use JSR 250 annotations in the web container. and also you can package entities in the web container. Also we have added the library module support in the application level. You can add a lib directory in the EAR level and any jars put in the lib directory will available to all modules in the EAR.

4. We implemented dynamic byte code generation for EJB wrappers and that greatly improves deployment of EJB applications. Most EJB applications should see between 30-70% improvement in deployment from OC4J 10.1.3 in identical configurations.

5. We have added a lot of new ANT tasks to make your life easier e.g. creation of data sources, JMS objects, shared libraries, etc.

Beside that we have a lot of bug fixes. So please try out and give us your feedback.

Here is link again : http://www.oracle.com/technology/tech/java/oc4j/10131/index.html

Oracle SOA Suite - Complete EJB3 and JPA Support

2006-08-15T14:36:00.000-07:00

Yesterday Oracle released Oracle Application Server 10g (10.1.3.1) Developer Preview. The goal for this release to simplify development and deployment of service-oriented applications and hence it is termed as SOA Release. The SOA suite provides complete set of service infrastructure components such as Enterprise Service Bus, BPEL, BAM and Web Services Manager for creating, deploying and managing services, all available in a single install.

If you are an enterprise java developer and do not care about SOA, OracleAS 10.1.3.1 has something for you too. O It has complete support for EJB 3 and Java Persistence API and has annotations support in the Servlet container. OC4J 10.1.3.1 includes TopLink Essentials as the EJB3 JPA Provider.

You can download JDeveloper 10.1.3.1 and OC4J 10.1.3.1 standalone and to build and deploy EJB3/JPA applications.

See EJB3 Resources for updated howtos, samples, articles, etc.

Developing a Spring-enabled Session bean

2006-08-14T23:47:00.000-07:00

In one of my blog entries last month I showed how you could access an EJB 3.0 Session bean from Spring 2.0 beans. One of the readers wanted to know whether it is possible to use Spring with EJB 3.0. Interestingly Spring documentation does not say anything about EJB 3.0 beans support with Spring 2.0. I managed to get this to working Spring 2.0 RC2 and in this article; I will show how you can develop a Spring-enabled EJB 3.0 Session bean.

Spring-enabled EJB 3.0 Session bean.

Spring provides abstract classes such as org.springframework.ejb.support.AbstractStatelessSessionBean and org.springframework.ejb.support.AbstractStatefulSessionBean that you can use to build a Spring-enabled EJB 3.0 session bean. You have to extend the abstract session bean class and implement the onEjbcreate method where you can retrieve the required bean instance from the bean factory as in the following example:

@Stateless
public class EmployeeFacadeBean extends
AbstractStatelessSessionBean implements EmployeeFacade
{
EmployeeServiceBean empService;

protected void onEjbCreate()
{
empService = (EmployeeServiceBean)
getBeanFactory().getBean("empService");
}

public Employee addEmployee(String empName, double sal) {

return empService.addEmployee(empName,sal);
}

..
}

Note that our stateless session bean EmployeeFacadeBean extends AbstractStatelessSessionBean. Note that we have implemented the onEjbCreate method that retrieves instance of EmployeeServiceBean from the bean factory.

The EJB deployment descriptor

The application context is passed to the Session Bean by using an environment variable named ejb/BeanFactoryPath in the deployment descriptor (ejb-jar.xml) as follows:


<session>
<ejb-name>EmployeeFacadeBean</ejb-name>
<env-entry>
<env-entry-name>ejb/BeanFactoryPath</env-entry-name>
<env-entry-type>java.lang.String</env-entry-type>
<env-entry-value>/howto-service.xml</env-entry-value>
</env-entry>
</session>

Note that the howto-service.xml contains the bean factory configuration that we see next. The howto-service.xml is packaged in the ejb-jar module.

Wiring all together with Spring configuration

The howto-service.xml contains the Spring configuration.
The EmployeeServiceBean uses EmployeeDAO that is injected using setter injection:

<beans>
…
<bean id="empService" class="oracle.ejb30.EmployeeServiceBean">
<property name="employeeDAO">
<ref bean="employeeDAO">
</ref>
</property>
..
</bean>

Remember that the Spring enabled EJB 3.0 Session bean (EmployeeFacadeBean) invokes the EmployeeService bean from the bean factory

empService = (EmployeeServiceBean) getBeanFactory().getBean("empService");

Client Code:

Let us assume that a servlet accesses the Spring-enabled EJB as follows:

public class InsertServlet extends HttpServlet
{
@EJB
private EmployeeFacade ef;

..

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String name = "";
Double sal = new Double(0);

name = request.getParameter("empName");
sal = Double.valueOf(request.getParameter("Sal"));
try
{
Employee emp = ef.addEmployee(name,sal);
System.out.println("Successfully persisted an employee");
request.setAttribute("emp",emp);
this.getServletContext().getRequestDispatcher("/jsp/success.jsp").forward(request, response);
}
catch(Exception e)
…
}

If you look at the above code you will see that the Servlet uses dependency injection using @EJB (Java EE) to get an instance of Spring-enabled EJB and then invoke its method.

Conclusion

After you package your application, you should be able to deploy and run the application that uses a Spring-enabled EJB 3.0 session bean. Note that I tested this with Oracle Application Server 10g and I expect it to work in other application servers that support EJB 3.0. In a follow-up blog, I will discuss how you can use Spring’s JpaTemplate with a container-managed EntityManager within a Java EE container.

Same house and same job but a new blog!

2006-08-10T22:45:00.000-07:00

Changes are part of our life! New car, new computer or new kids are always fun! They bring excitement to life. But sometime we have emotional attachment to old things, old houses, etc. And I had the same with my old blog-site (http://radio.weblogs.com/0135826/) and was resisting for a change. I used Radio UserLand for more than two and half years and although I never liked it user interface, ability to restore old blogs I was still emotionally attached that being my first blog site.

Finally I decided to desert it. Some shortcomings in Radio Userland literally drove me crazy and I was not able to blog almost for a month after my laptop crashed! I had to pay Price for Carelessness.

My old blog site was getting fairly good number of hits averaging around 300 hits a day with some days around 2000-2500 hits. It has a good number of popular and controversial blogs that were linked from many web sites including TheServerSide.com, JavaWorld, java.net, etc and hence leaving the old blog home was not an easy decision. I will try to restore some of my popular old blogs in the new blog site so that these are not lost when my license expires with Radio UserLand and they trash these pages. So stay tuned when I return to normal bogging schedule!