Using the MouseTrack.java program and the example1.html file in ~mem/classes.
 
Do the following
        % appletviewer -debug example1.html
                Loading jdb ...
                0xee301bb8:class(sun.applet.AppletViewer)
        > stop at CatchMe:124
                Breakpoint set at CatchMe:124
        > run
                run sun.applet.AppletViewer example1.html
                running ...
                Breakpoint hit: CatchMe.<init> (MouseTrack.java:124)
                Thread-6[1] list
                120 private boolean debug = true;
                121
                122 /** Constructs a new CatchMe object. */
                123 public CatchMe(int width, int height, MouseTrack applet) {
                124 => w = width;
                125 h = height;
                126 gameEngine = applet;
                127 }
                128
        Thread-6[1] print width
                "width" is not a valid id or class name.
 
Problem:
I'm stopped in a constructor method.
I say print width (where width is one of the parameters).
It sez:
        "width" is not a valid id or class name.