[8] Sun released the Java HotSpot virtual machine and compiler as free software under the GNU General Public License on November 13, 2006, with a promise that the rest of the JDK (which includes the Java Runtime Environment) would be placed under the GPL by March 2007, "except for a few components that Sun does not have the right to publish in source form under the GPL".

[12] Included in the list of encumbered parts were several major components of the Java graphical user interface (GUI).

Sun stated that it planned to replace the remaining proprietary components with alternative implementations and to make the class library completely free.

Another project pending formalization on the Porters Group is the Haiku Java Team led by Bryan Varner.

[20] In December 2007, Sun moved the revision control of OpenJDK from TeamWare to Mercurial (and later to Git and GitHub), as part of the process of releasing it to open-source communities.

Initially, the external patch submission process was slow[25] and, until September 2008, commits to the codebase were only made by Sun engineers.

[29] On 25 September 2013, Microsoft and Azul Systems collaborated to create Zulu,[30] a build of OpenJDK for users of the Windows Azure cloud.

It is also possible to get Zulu on Amazon Web Services[31] via Canonical's Juju Charm Store,[32] the Docker Hub,[33] and Azul Systems repositories.

[35][36] Since April 2016 there are unsupported community builds of OpenJDK for Microsoft Windows on GitHub in the project ojdkbuild[37] which are released in pace with updates for Oracle JDK.

From build 8u151 on, the MSI-installer offers an optional component for using Java Web Start based on the IcedTea-Web project.

OpenJDK 11, released in September 2018, received 20% of external fixes[39] and brought 17 new JEPs (features), out of which 3 were contributed by the community.

[82][83] On November 5, 2007, Red Hat signed both the Sun Contributor Agreement and the OpenJDK Community TCK License.

In May 2008, the Fedora 9[15][85] and Ubuntu 8.04[86] distributions included IcedTea 6, based completely on free and open source code.

[95] In July 2009, an IcedTea 6 binary build for Ubuntu 9.04 passed all of the compatibility tests in the Java SE 6 TCK.

[97] On Android Nougat, OpenJDK replaced the now-discontinued Apache Harmony as the Java libraries in the source code of the mobile operating system.