No Stack Information - V(Unknown Source)

I am having a problem with my app, and wondering why I am not getting any stack information just;

    java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
            at com.x.y.z.()V(Unknown Sour开发者_Python百科ce)

I am building using an Ant script - do I need to fiddle with some sort of compilation verbosity setting?

P.S. I am not interested in the NoClassDefFoundError, just the lack of stack trace.

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After some googling I found it.

Need to add the arguments;

debug="true" debuglevel="lines,vars,source"

, to the javac task.