Can I get recommendations of free and easy tool(s) that can generate JUnit tests based on existing code?
Either as a stand-alone application or pref. an Eclipse-plugin.
Well, depends on what do you need your tests for…
If just to have tests coverage and basic behavior tested – then yes, use can use test generators.
If you are serious about the project and plan to expend it, see the future of the project – then it would be really better to create good unit tests in traditional way.