How do I pipe the Java console output to a file?

Question

I found a bug in an application that completely freezes the JVM. The produced stacktrace would provide valuable information for the developers and I would like to retrieve it from the Java console. When the JVM crashes, the console is frozen and I cannot copy the contained text anymore.

Is there way to pipe the Java console directly to a file or some other means of accessing the console output of a Java application?

Update: I forgot to mention, without changing the code. I am a manual tester.

Update 2: This is under Windows XP and it's actually a web start application. Piping the output of

javaws jnlp-url

does not work (empty file).

Answer 1

(If you can modify the code) you can set the System.out field to a different value:

System.setOut(new PrintStream(new FileOutputStream(fileName)));

If you are running a script (invoking the program via java) from Unix you could do:

/path/to/script.sh >& path/to/output.log

Answer 2

Actually one can activate tracing in the Java Control Panel. This will pipe anything that ends up in the Java console in a tracing file.

The log files will end up in:

• <user.home>/.java/deployment/log on Unix/Linux
• <User Application Data Folder>\Sun\Java\Deployment\log on Windows
• /~/Library/Caches/Java/log on OS X