OpenJDK is the free version of the Java development platform.
The OpenJDK project consists of a number of components. Principally these are HotSpot (the virtual machine), the Java Class Library and the javac Java compiler.
The web browser plugin and Web Start which are part of Oracle Java are not included in OpenJDK. Sun previously indicated that they would try to open source these components but neither Sun nor Oracle have done so. The only currently available free plugin and Web Start implementation are those provided by IcedTea. More Info »
Supported JDK versions
OpenJDK was initially based only on the JDK 7 version of the Java platform.
There are several separate OpenJDK projects:
- The OpenJDK 8 project (http://openjdk.java.net/projects/jdk8/ ), which will be the basis for JDK 8.
- The OpenJDK 7u project (http://openjdk.java.net/projects/jdk7u/ ), which is based on JDK 7 and produces updates to the existing Java 7 releases.
- The OpenJDK 6 project (http://openjdk.java.net/projects/jdk6/ ), which is based on JDK 7, retrofitted to provide an open-source version of Java 6.