RESTEasy hides real exception

My code is throwing an exception (due to a bug). In the log, I see:

org.jboss.resteasy.spi.UnhandledException: java.lang.NullPointerException
    at org.jboss.resteasy.core.SynchronousDispatcher.handleApplicationException(SynchronousDispatcher.java:323)
    at org.jboss.resteasy.core.SynchronousDispatcher.handleException(SynchronousDispatcher.java:199)
    at org.jboss.resteasy.core.SynchronousDispatcher.handleInvokerException(SynchronousDispatcher.java:175)
    at org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:529)
    etc...

The stack of the actual e开发者_Python百科xception is not logged. If I wrap my code in a try..catch and log the caught exception I can verify that my code is at fault. No other library in my system does this, even for deeply-wrapped exceptions, so it must be a problem in RESTEasy, perhaps in UnhandledException?

Is there a way to get around this behavior? I can't think of a good reason why it should be hiding the actual exception.

• Jetty
• Java
• Spring 3.0.3
• RESTEasy 2.0.1GA

Do you have an ExceptionMapper? See Chapter 27, Exception Handling, in the RESTEasy documentation.

I used RESTEasy to add REST to an existing system, and the existing system has a weird way of wrapping exceptions within exceptions, so my ExceptionMappers do a lot of unwrapping.

Throwable t = exception;
while (t.getCause() != null) {
  t = t.getCause();
}
t.printStackTrace();

I don't use RESTeasy, but it appears to be a dispatch mechanism for RESTful web services.

Assuming this is the case, then it has different design goals from other libraries: they are invoked from your application, but RESTeasy is responsible for invoking your application. It therefore has to protect itself from poorly written code. A "last ditch" exception handler is a common way to do this; you'll see the same thing in Swing.

Whether or not it should log the uncaught exceptions is a different matter. Perhaps there's a configuration option to do this. Or perhaps you need to add a couple lines of code. It is open-source, after all, and I'm sure the maintainers would appreciate a well-written bug report with patch.

Yes, your exception is swallowed by RESTeasy, wrapped in UnhandledException and logged. But your exception lies too deep within to be included in the stacktracs.

To print out your exception to the console, you could append the following to 'WEB-INF/classes/logging.properties'

org.apache.catalina.core.ContainerBase.[Catalina].level = FINEST
org.apache.catalina.core.ContainerBase.[Catalina].handlers = java.util.logging.ConsoleHandler