How to find unused/dead code in java projects

Question

What tools do you use to find unused/dead code in large java projects? Our product has been in development for some years, and it is getting very hard to manually detect code that is no longer in use. We do however try to delete as much unused code as possible.

Suggestions for general strategies/techniques (other than specific tools) are also appreciated.

Edit: Note that we already use code coverage tools (Clover, IntelliJ), but these are of little help. Dead code still has unit tests, and shows up as covered. I guess an ideal tool would identify clusters of code which have very little other code depending on it, allowing for docues manual inspection.

Answer 1

There are tools which profile code and provide code coverage data. This lets you see (as code is run) how much of it is being called. You can get any of these tools to find out how much orphan code you have.

Answer 2

User coverage tools, such as EMMA. But it's not static tool (i.e. it requires to actually run the application through regression testing, and through all possible error cases, which is, well, impossible :) )

Still, EMMA is very useful.

Answer 3

I found Clover coverage tool which instruments code and highlights the code that is used and that is unused. Unlike Google CodePro Analytics, it also works for WebApplications (as per my experience and I may be incorrect about Google CodePro).

The only drawback that I noticed is that it does not takes Java interfaces into account.