Recently I used JRebel to do hot deployment of a complicated Web application on BEA WebLogic 12. I found it is very easy to setup and give me a great improvement in web development. I can see the result of my Java or xhtml code changes on the website in a flash. Here is a summary of what I did to enable JRebel with WebLogic and Eclipse:
1. Download JRebel plugin for Eclipse, validate with a license.
2. Enable the Eclipse projects with JRebel by "Add JRebel Nature".
3. Check the auto generated rebel.xml file for each java project to make sure the monitored target directories are correct. Only thing I needed to change is the Web directory since we didn't put our web stuff under default WebContent directory.
4. Build the war file as usual to the deployment directory.
5. Add jrebel.jar to the weblogic domain home directory. Add this to the startWebLogic.cmd file:
Add -javaagent:%DOMAIN_HOME%\jrebel.jar -Drebel.remoting_plugin=false to the `set SAVE_JAVA_OPTIONS=` line.
6. Start the Weblogic server and you should see the projects' target directories are monitored by JRebel for changes now.
Here is how it works behind the scene:
JRebel will monitor and detect changes in the target directories for compiled Java files or copied over web based files. Eclipse is moving the changes from source to target directories (compile or copy). Weblogic will allow JRebel to hot swap the files whether it is a Java class, or Xhtml or a properties file.
Combining JReble with Eclipse remote debugging, the Web development and debugging just becomes really easy!