Arpwatch for Yosemite?
You can simply right-click /Applications/Mocha.app/Contents/Resources/Java/mocha.jar and launch it with the Java Launcher. I don't know if the JRE version contains this "app" - at least the JDK does.

After modifying the innards (e.g the info.plist &amp; JavaApplicationStub) it may also be possible to launch the app itself without installing Java6, but I didn't get this to work.