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.
KeyStore Explorer is a free GUI replacement for the Java command-line utilities keytool and jarsigner.
An open source command line RatioMaster with an optional WebUI.
Interactive command line JMX client