java: stacktrace with no line number

When getting a Java log exception with no line number and instead a message saying "Unkown source", just like you can see bellow:

...
at com.vgn.cgd.webApp.actions.pci.impl.ppcLoadAction.doExecute(Unknown Source)
...

It may be caused by Ant that by default omits the debug information. If it's the case you can easily solve this by add 2 attributes to your ant target javac:

....
<javac ... debug="on" debuglevel="lines,vars,source">
....


And there you go, the line number of the exception will appear in your log.