Diamond Edge Applet Designer
A Visual Basic add-in module. Convert your VB project to Java with one button click. Free trial download.

j2c/CafeBabe
Java .class to C translator.

Languages for the Java VM
A list of tools for programming to the Java virtual machine using a language other than Java itself.

Harissa
A Java environment that includes a compiler from Java bytecode to C and a Java interpreter. Distributed free, as Open Source under the Gnu Public Licence.

JCC - A Java to C converter
A direct Java to C translator. Unlike other translators JCC does not convert Java class files, but instead processes Java source code directly.

Jolt
This is a hackers only prototype of a Java bytecode to C translator written in Java. Source download.

Toba
Java-to-C Translator: translates Java class files into C source code to allow making, fast, directly executable programs that avoid the overhead of interpretation. For stand-alone applications, not applets.

C2J
Translates C programs to Java programs, by Novosoft. Run C application through C2J and get one .class file. Standard ANSI C runtime library, ANSI C, K&R C fully supported. C2J itself, YACC, SQL Pretty Formatter, and PGP were succesfully translated to Java by C2J as part of test process.