ANTLR Parser Generator http://www.antlr.org
Hibernate Object Persistence Framework https://www.hibernate.org/
Java Data Objects (JDO) Object Persistence Framework
Toplink Object Persistence Framework  
OSWorkflow http://www.opensymphony.com/osworkflow/
Seam Web 2.0 Application Development Framework http://www.jboss.com/products/seam/
Spring Model-View-Controller / Aspect-Oriented Programming Framework http://www.springsource.org/
Stripes Web Application Development Framework http://www.stripesframework.org
Struts 2 Web Application Development Framework http://struts.apache.org/2.x
Terracotta Application Scaling Framework http://www.terracotta.org/
Wicket Web Application Framework http://wicket.apache.org/