Java compiler

A Java compiler is a compiler for the programming language Java. The most common form of output from a Java compiler is Java class files containing platform-neutral Java bytecode, but there are also compilers that gives optimized native machine code for a particular hardware/operating system combination.

Most Java-to-bytecode compilers, Jikes being a well known exception, do virtually no optimization, leaving this until run time to be done by the JRE.^{[citation needed]}

The Java virtual machine (JVM) loads the class files and either interprets the bytecode or just-in-time compiles it to machine code and then possibly optimizes it using dynamic compilation.

A standard on how to interact with Java compilers programmatically was specified in JSR 199.

Major Java compilers

As of 2012, the following are major Java compilers:^{[citation needed]}

The Java Programming Language Compiler (javac), included in the Java Development Kit from Oracle Corporation, open-sourced since 13 November 2006.
GNU Compiler for Java (GCJ), a part of the GNU Compiler Collection, which compiles C, C++, Fortran, Pascal and other programming languages besides Java. It can also generate native code using the back-end of GCC.
Eclipse Compiler for Java (ECJ), an open source incremental compiler used by the Eclipse project.

References

External links

Sun's OpenJDK javac page
JSR 199 Java Compiler API Java Specification Request for invoking the Java compiler from a Java program
A Formal Introduction to the Compilation of Java, Stephan Diehl, "Software - Practice and Experience", Vol. 28(3), pages 297-327, March 1998.