Define a library that points to the classes and sources for your app.

  Tools | Configure libraries
    Click 'New...' in the lower left
    Give the library a name, call ie DebugFoo.
    Set DebugFoo's class path to contain all of the jars your app uses.
    Set DebugFoo's source path to the top of the tree(s) where  your app's
      sources live.
    Ok, Ok

It is critical to set the library's source path properly, otherwise the debugger will not display your actual source, but a decompiled stub of the classfile.

Now tell the empty project to use this library.

  Project Properties | Paths | Required Libraries
  Add
  Select DebugFoo
 

  Project Properties | Run, select the app's main class from the browser.

If there's a file you need to set a breakpoint in, use Run | Add Breakpoint to add breakpoints.

You shouldn't need to compile anything unless your existing classes lack debug information.
2001-Jun-20 2:04pm gyles19@visi.com