The Eclipse Checkstyle plug-in integrates the Checkstyle Java code auditor into the Eclipse IDE. The plug-in provides real-time feedback to the user about violations of rules that check for coding style and possible error prone code constructs.
Chex4j allows you to document and enforce @pre and @post conditions of method calls with runtime or build time class file instrumentation. Conditions run as fast as normal code.
Code Critick is able to heuristically evaluate aspects of OO design quality, by using metrics. It also supports "code coloring" visualization -- shading lines of code by metrics. Originally developed at the University of Canterbury.
Provide metrics calculation and dependency analyzer plugin for the Eclipse platform. Measure metrics with avg and std deviation and detect cycles in package and type dependencies. Continuation of work from http://sourceforge.net/projects/metrics.
Eclipastie is an open source Eclipse (3.3+) plugin (EPL license) which seamlessly copy and pastes text from within Eclipse to pastebins like Pastie (http://pastie.org) or LodgeIt (http://paste.pocoo.org/)