v 6.23.0|PMD
PMD is a source-code analyzer. It can identify common programming flaws such as empty catch blocks, unused variables, and unnecessary object creation. It supports JavaScript, XML and XSL.
The following plugins are available:
CPD, or copy-paste detector, is also part of PMD. CPD detects duplicate code in Java, C++ and C#, PHP. Ruby, Fortran and JavaScript are all possible.