Cenqua has released Clover 2.0, a $1200 payware test coverage tool.
Clover modifies the source code to enable it to follow which statements are executed when, and keeps a running count of how many times each statement is executed during the test suite. Any statement that executes zero times is not being tested.
I use Clover with Ant, but there's also an Eclipse plug-in.
Clover can generate test coverage reports in
XML, HTML, PDF, or via a Swing Viewer.
Version 2.0 adds cyclomatic complexity calculations, a Maven 2 plug-in, coverage clouds and can tell you
which tests hit what code. Upgrades from 1.x are $600 or free if you bought in the last year.