Automatically Executing a Client Application Archive

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!