Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard. By default it supports the Google Java Style Guide and Sun Code Conventions, but is highly configurable. It can be invoked with an ANT task and a command line program.
Spoon is a metaprogramming library to analyze and transform Java source code. :spoon: is made with :heart:, :beers: and :sparkles:. It parses source files to build a well-designed AST with powerful analysis and transformation API.