The JDebugToolJava debugger from debugtools.com LLC is a:
Standalone graphical Java debugger.
Built on top of the standard JPDA (Java Platform Debugger Architecture).
Is itself written in Java.
Features an intuitive and graphical Java Swing GUI.
Context-sensitive Help Viewer.
JDebugTool 4.3.1 new features:
In this release, simply click on a variable in the source window, and then right-click and select Inspect (to drill down into an object's fields), toString (to invoke the toString method), or Watch (to add to a Watch Panel).
Source code tool tips now also display interface names that an object implements.
30 day trial. Personal, Company and Academic licenses.