The first free project to offer substantial parts of Java platform functionality was likely guavac, which began some time before November 1995.
Another event in May 2005 was the announcement that OpenOffice.org 2.0 would depend on Java features which free software implementations couldn't provide.
On November 13, 2006, Sun released its compiler, javac, under the GNU General Public License.
[5] As of September 2007, as well as javac, Sun has released the code of HotSpot (the virtual machine) and almost all the Java Class Library as free software.
[25][citation needed] In September 2013, Azul Systems released Zulu, a free, open source build of OpenJDK for Windows Server and the Microsoft Azure Cloud.
Zulu is certified compliant with Java SE 8, 7 and 6 using the OpenJDK Community Technology Compatibility Kit.
[27] In 2017, the Eclipse Foundation released AdoptOpenJDK, now named Adoptium, whose main goal is "to promote and support free and open-source high-quality runtimes and associated technology for use across the Java ecosystem."