Sometimes your Java source files are not in the same directory as the .class or .jar files. You can use the $JAVASRCPATH environment variable to specify the directories in which dbx should look for Java source files. The following example causes dbx to look in the listed directories for source files that correspond to the class files being debugged.
JAVASRCPATH=.:/mydir/mysrc:/mydir/mylibsrc:/mydir/myutils