A bytecode to C translator . Jonathan Meyer's Jasmin assembler uses a nice assembler-like language, and is distributed under the GNU General Public License. Javaa, bytecode assembler with an interface similar to javap output. Jobe, a java obfuscator is freely available as shareware, but without source code. A license is required for commercial use.
Registered users get access to the source code.
Hanpeter van Vliet's Mocha decompiler generates very readable java source code from bytecode. Mocha is available free of charge, but without source code. Hanpeter also offers Crema, an obfuscator. Hanpeter has passed away . Language to Java Per Bothner's Kawa scheme compiler compiles a large subset of R4RS scheme to java bytecode.