http://www.netbeans.org/
NetBeans Developer is a Java IDE written in pure Java. The IDE is based on JFC, and uses it's full feature-set. Full support of JavaBeans, use the BeanWizard to generate your own beans in minutes. Integrated full-featured text editor, debugger, compiler, pluggable Look & Feel, and Form Editor with advanced layout manager support.
Source: OS2 Warp News and Rumors