You may notice a slight change in the behaviour of OC4J 10.1.3.1 with the JSP engine.
In previous releases, when an error occurs in the translation or runtime execution of a JSP page, the container would return the exception, message and a stacktrace to the client. It even included the line in the JSP page where the error occurred.
When developing, this rock'd. What more could you want -- error, stacktrace, offending line in JSP.
In the 10.1.3.1 release, the behaviour has changed so that instead of returning all the gory details to the client, a generic error message is presented. The details are now written into the log file for the application.
When running a production app, this is better -- clients don't need to see that level of detail.
The good news for developers is that the behaviour can be modified so that the error details are again reported to the client by configuring the web module to be in development mode.
This is done using the orion-web.xml of the application by setting the developer attribute of the orion-web-app element to true.
This can be done in several ways.
First off, you can put an orion-web.xml file into the WEB-INF directory of the Web module, and provide this setting in the file.
If you don't want to do that, and deploy the application using Application Server Control (ASC) then you can edit the deployment plan when the application is deployed and configure the development mode . Choose to edit the deployment plan, locate the Web module in question and set developer attribute to true.
If you are using JDeveloper and deploying the application to an external OC4J instance (ie not its embedded server), then you can use the Deployment Plan editor that it invokes to do the exact same thing. It's actually a really sweet capability.
When the deployment plan editor appear, locate for the Web module for which you want to enable development mode, then click in the "development" field and set the value to true.
Continue with the deployment.
This deployment plan setting will be applied to the application when it is deployed to the OC4J instance.
Now when the application is accessed and an error occurs, OC4J will determine that the Web module is running in development mode and return all the gory details to the client.
From the JDeveloper Deployment Plan editor, you can even choose to save the settings after you configure them so they can be loaded next time.