Direct Comparison - Findbugs vs PMD vs Checkstyle

	Findbugs [1]	PMD [3]	Checkstyle [2]
Version	3.0.0	5.2.2	6.1.1
License	Lesser GNU Public License	BSD-style license	Lesser General Public License
Purpose	Potential Bugs   finds - as the name suggests - bugs in  Java byte code	Bad Practices  looks for potential problems, possible bugs,  unused and sub-optimal code and over-  complicated expressions in the Java source  code	Conventions   scans source code and looks for coding standards,  e.g.  Sun Code Conventions, JavaDoc
Strengths	- finds often real defects - low false detected rates - fast because byte code - less than 50% false positive	- finds occasionally real defects - finds bad practices	- finds violations of coding conventions
Weaknesses	- is not aware of the sources - needs compiled code	- slow duplicate code detector	- can't find real bugs
Number of rules	408	234	132
Rule Categories	Correctness  Bad practice  Dodgy code  Multithreaded Correctness  Performance Malicious  Code Vulnerability  Security Experimental  Internationalization	JSP   - Basic JSF   - Basic JSP  XSL   - XPath in XSL  Java   - Design   - Coupling   - Jakarta Commons Logging   - Basic   - Strict Exceptions   - Security Code Guidelines   - Java Logging   - Android -Controversial   - Comments   - Type Resolution   - Empty Code   - String and StringBuffer   - Code Size   - Braces   - Unused Code   - Unnecessary   - J2EE   - JavaBeans   - Migration   - Import Statements   - JUnit   - Naming   - Finalizer   - Optimization   - Clone Implementation  Ecmascript   - Basic Ecmascript   - Unnecessary   - Braces   XML   - Basic XML	Annotations  Block Checks  Class Design  Coding  Duplicate Code  Headers  Imports  Javadoc Comments  Metrics  Miscellaneous  Modifiers  Naming Conventions  Regexp  Size Violations