Issue580170

We're running jython within Tomcat. Due to a Python 
script programming error we ran into an 
OutOfMemoryError. Py.java handles this error by 
eventually calling System.exit(), which crashes Tomcat. 
In general, for the purpose of running jython from within 
another Java application it would be good to remove all 
the System.exit() calls. 

System.exit occurs in jython.java and Py.java.  Look at maybeExit and the SystemExit class and Py.java.

It would be great to have a test case that reproduces this.  From running this code in the interpreter:
>>> import java.lang as jl
>>> a = []
>>> for z in xrange(6000000):
...    a.append(jl.Long(z))

The OutOfMemory error is produced but it does not cause Jython to exit.

leouser

This code exists in PyObject:

} catch (PyException e) {
    if (e.value instanceof PyJavaInstance) {
        Object t = e.value.__tojava__(Throwable.class);
        if (t != null && t != Py.NoConversion) {
            throw (Throwable) t;
        }
    } else {
        ThreadState ts = Py.getThreadState();
    if (ts.frame == null) {
        Py.maybeSystemExit(e);
    }
    if (Options.showPythonProxyExceptions) {
        Py.stderr.println(
             "Exception in Python proxy returning to Java:");
        Py.printException(e);
    }
}

This calls the maybeSystemExit() method which probably is a bad thing for the PyObject class given that so many classes inherit from this class. Could this be related to this bug?

System.exit is never called for OutOfMemoryError -- maybe it once did.

System.exit is only called in the event of an actual explicit call to
exit from Python code (for example a call to exit()).  This is no more a
problem than having Java code call System.exit().