Java is a platform-independent programming language that supports various operating systems. The source code is first compiled into bytecode and then translated into the respective machine language for the target system by the Java Runtime Environment. For this purpose, the Java Runtime Environment must be installed, which supports Microsoft Windows, Linux, Solaris, Mac OS X, AIX and many other operating systems. Java also plays an important role in embedded systems such as cell phones, PDAs, tablets, cars and TVs.
At the end of the second quarter of 2007, Sun announced that Java would be released under the terms of the GPL version 2 license. Various developers have written free software for interpretation such as GNU Compiler for Java, Kaffe, GNU Classpath, Apache Harmony or IcedTea.