Name: jl125535 Date: 07/26/2004


A DESCRIPTION OF THE REQUEST :
For a while now, when running java from the command line, you've been able to detect deadlock and perform rudimentary profiling by using control-break under windows or kill -3 pid under Unix. This signal causes the JVM to dump a stack trace for each thread as well as provide some other useful information. Under JavaWebStart, on windows at least there is no easy way of getting this information. This is a request to add the same facility to JavaWebstart, either from the webstart console, from the control-panel, or by some other means if more appropriate.

JUSTIFICATION :
Deadlocked or high CPU states can be hard to reproduce, it is extremely useful to be able to get diagnostic information when they do occur.

Webstart applications have this need just as much as other applications. Evidence for this need in the community include the unofficial java web start FAQ.

http://lopica.sourceforge.net/faq.html#debug

Starting Java Web Start apps so a debugger can connect is clearly a requirement, this functionality would avoid some of the need to use a debugger. Obviously for a lot of problems connecting a debugger is appropriate, but this can be difficult, as shown by the question in the unofficial JWS FAQ.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Type control-break in the Java Console and get the thread stack traces as you do from the command line.
ACTUAL -
As far as I can see there is no way of getting this information in the current implementation without attaching a debugger through a fairly involved process.

CUSTOMER SUBMITTED WORKAROUND :
Attach a debugger, or convert the app to a command line application.
(Incident Review ID: 289844)
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