Since JDK 10, the effort to produce an open-source reference implementation of the Java SE Platform was moved over to the JDK Project. OpenJDK was initially based only on the JDK 7 version of the Java platform. The experimental -XX:+EnableJVMCIProduct flag enables the use of Graal JIT (JEP 317). OpenJDK 9+ supports AOT compilation ( jaotc) using GraalVM (JEP 295). The only currently available free plugin and Web Start implementations as of 2016 are those provided by IcedTea. Sun previously indicated that they would try to open-source these components, but neither Sun nor Oracle have done so. The web-browser plugin and Web Start, which form part of Oracle Java, are not included in OpenJDK. The OpenJDK project produces a number of components: most importantly the virtual machine ( HotSpot), the Java Class Library and the Java compiler ( javac).

OpenJDK is the official reference implementation of Java SE since version 7. Were it not for the GPL linking exception, components that linked to the Java Class Library would be subject to the terms of the GPL license. The implementation is licensed under the GPL-2.0-only with a linking exception. It is the result of an effort Sun Microsystems began in 2006. OpenJDK ( Open Java Development Kit) is a free and open-source implementation of the Java Platform, Standard Edition (Java SE). Linux, FreeBSD, macOS, Microsoft Windows, OpenIndiana several other ports in progress

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