By Compaq. Detects, at compile time, common programming errors that ordinarily are not detected until run time, and sometimes not even then; for example, null dereference errors, array bounds errors, type cast errors, and race conditions.

A command line tool employing static analysis on your JAVA source code. Potential bugs and weak points are reported and the manual describes how the source code can be improved. [Freeware]

Checks code and finds bugs, inconsistencies, and synchronization problems by doing data flow analysis and building a lock graph. [Freeware, source provided]

A static Java source code analyzer that detects locking and threading issues, performance and scalability problems, and checks complex contracts such as Java serialization by performing type, data flow, and lock graph analysis. [Freeware]

A utility for finding problems in Java code. PMD does this using static analysis; that is, analyzing the source code without actually running the program.

A static error checker. It detects subtle run-time errors in Java source code and produces information for program understanding. [Commercial]