I'm looking for a technique to tell if a class file contains debug
symbols (meaning that it was built with the -g flag enabled).   The
simpler the technique, the better.

We aren't getting line numbers in our stack traces and are trying to
determine why.  Thus, the first thing we'd like to check is whether any
debug symbols ended up in the class file at all.

As added info, here's what we are using in Ant, in case it's an Ant
error.

<javac srcdir="${app.source.dirs}" fork="yes"
    memoryMaximumSize="512m"
    debug="on"
    executable="${app.gemstonejava.dir}/bin/javac"
    bootclasspath="${app.bootclasspath}"
    classpath="${app.classpath}"
    destdir="${app.classes.dir}">
   
    <compilerarg value="-g:lines">
    </compilerarg>
</javac>