Genetic Programming (JGProg) is an open-source pure Java implementation of a strongly-typed Genetic Programming experimentation platform. http://jgprog.sourceforge.net/
An easy to learn evolutionary computing framework written for Java 5. Genetic programming is implemented through fast stack-based linear programs. http://cui.unige.ch/spc/tools/n-genes/
Contains a Java Applet for symbolic regression using GP. It allows the import of data and the export of the resulting equations to spreadsheet applications like Excel. http://www.potschi.de/sr/
A group of graduate students in the Department of Computing and Information Sciences at Kansas State University with an emphasis to genetic programming. http://geckies.user.cis.ksu.edu
A (distributed) framework for breeding programs for distributed systems like sensor nodes. Using this open source (LGPL) Java framework, you can easily evolve assembler-style programs. http://sourceforge.net/projects/dgpf