Question

I am trying to build a general exception handler for a swing application as described here: http://www.javaspecialists.eu/archive/Issue081.html

I work in jython (python syntax getting compiled to java and executed). My code looks roughly like this (updated):

def launcher(func):
    class launcherThread(Runnable):
        def __init__(self):
            super(launcherThread, self).__init__()

        def run(self):
            func()

    #trying to get the name which can be used to instantiate this in java
    cls = ExceptionGroup().getClass()
    fullName = cls.__module__ + '.' + cls.__name__

    System.setProperty("sun.awt.exception.handler", fullName)
    Thread(ExceptionGroup(), launcherThread(), 'Cross ExceptionHandlerThread').start()

class ExceptionGroup(ThreadGroup):
    def __init__(self):
         super(ExceptionGroup, self).__init__("HardenedGroup")

    def uncaughtException(self, thread, exception):
        #make a fancy dialog displaying str(exception)

If I test it it works fine however in the production enviornment it failes.
For testing I launch my program in Eclipse (PyDev), the production enviornment is a third party application written in Java, that has a Jython console build in. The application supports adding of custom menu entries, and putting jython scripts on these.

The main difference I see between testing and production enviornment is that in the production enviornment the swing threads are allready started (the third party application utilitizes swing). Does this cause my ThreadGroup setting to fail, or is there another reason why this is not working?

How can I get the Involved threads (exceptions ar thrown as a result of buttonActions) to check their defaultException handlers? If (as I am afraid) it should turn out that the third party installed its own handler (all exceptions are written to a log file) how can I make a new swing worker thread? (I don’t want to catch the exceptions created by the host application after all)

Question recap:
1. How can I check which threads are started for the function func passed into the launcher function and see thier uncaught exception handler?
2. Can I enforce a seperate swing dispatcher for my gui part and the main applications gui part? (If I exitOnClos on a frame of my add in, the third party application closes)?

Update:
Considering the anwser from lbalazscs I am trying to use the sun.awt.exception.handler property, but it has no effect, the exceptions still end up in the log file (applications dfeault behaviour). Am I using it right? (p.s.: I am on Java 1.6)

Answer 1

If you have Java 5 or higher, you can also use Thread.setDefaultUncaughtExceptionHandler(), which is also described in a newer “Java Specialists’ Newsletter”:

http://www.javaspecialists.eu/archive/Issue089.html

And here is the newest Java 7 version:

http://www.javaspecialists.eu/archive/Issue196.html

Also see this:
Why bother with setting the "sun.awt.exception.handler" property?

EDIT: This is how I use Thread.setDefaultUncaughtExceptionHandler (in Java…):

public static void setupGlobalExceptionHandling() {
    Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread t, Throwable e) {
            handleException(e);
        }
    });
}