Free Java Compilers

Java Platform, Standard Edition
Tools for developing and testing programs written in the Java programming language. The link for the Java Development Kit 6 can be found by clicking the JDK button.

Jikes Java Compiler
This free Java compiler is available for several platforms including Win32. It was formerly hosted by IBM, but is now a Sourceforge project.

GCJ Java Compiler
The GNU Java Compiler that can compile Java source code to native machine code, Java source to Java bytecode, and Java bytecode to native machine code.

Jasmin Java
Jasmin is an assembler for the Java Virtual Machine. It takes ASCII descriptions of Java classes, written in a simple assembler-like syntax using the Java Virtual Machine instruction set. It converts them into binary Java class files, suitable for loading by a Java runtime system.

Java Bytecode Assembler
The Java Bytecode Assembler (or simply Assembler) is a program that converts code written in "Java Assembly Language" into a valid Java .class file. This provides developers a simple means of either programming directly in Java assembly language or making Java bytecodes the target of a compiler. It eliminates the need for developers to generate the constant pool, keep track of code lengths, calculate offsets, and perform other mundane tasks.

Toba Java-to-C Translator (JDK 1.1 only)
Toba translates Java class files into C source code. This allows the construction of directly executable programs that avoid the overhead of interpretation. Toba deals with stand-alone applications, not applets. (JDK 1.1 only)