"It turns out that while the JVM will not track the actual type arguments for instances of a generic class, it does track the actual type arguments for subclasses of generic classes" (And for interface implementations, too)
JavaRebel is a JVM plugin (-javaagent) that enables to reload changes made to Java class files on-the-fly, saving developers the time that it takes to redeploy an application or perform a container restart.
APIviz is a JavaDoc doclet which extends the Java standard doclet. It generates comprehensive UML-like class and package diagrams for quick understanding of the overall API structure.
F. Steeg, C. Benden, und P. Samuelsdorff. Poster presented at the Twelfth International Conference on Functional Grammar. Sao Jose do Rio Preto, Brazil: Universidade Estadual Paulista., (2006)