| created on | September 5, 2022 |
All JDKs listed here are compliant to the TCK standard.
The OpenJDK community works on a free, open-source implementation of the Java SE standard. Oracle contributes heavily to the project, and it is the basis for both Oracle OpenJDK builds and Oracle JDK.
Oracle contributes to OpenJDK, providing updates for the corresponding Oracle OpenJDK build, until the next version comes out. Other vendors continue to provide updates for that OpenJDK version, while Oracle maintains its patches for Oracle JDK. This means that the Oracle JDK can differ from OpenJDK binaries produced by other providers, and this has always been the case.
For consistency, OpenJDK volunteers extend the update cycle for OpenJDK versions deemed identical to LTS versions of the Oracle JDK. There are a lot of people and organisations contributing to the OpenJDK, and in reality, they maintain the source code for a more extended period.
Oracle’s OpenJDK is licensed under the GNU General Public License, version 2, with the Classpath Exception, which allows free personal and commercial use of the JDK. The Classpath Exception part of the GPL V2 license allows distribution of programs based on OpenJDKs without the being obliged to provide the source code. This is especially important for some if not most commercial projects.
" As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. "
GNU General Public License, version 2, with the Classpath Exception, https://openjdk.org/legal/gplv2+ce.html
Oracle’s commercial JDK is licensed under the Java SE OTN License (OTN) and production use beyond the limited free grants of the OTN license will require a fee.
Here is the most relevant part of the corresponding section of the Oracle Technology Network License Agreement for Oracle Java SE:
Azul Platform Core (Azul Zulu) is a free, 100% open-source, drop-in replacement for standard OpenJDK or Oracle JDK.
Azul Platform Prime (Azul Zing) is a heavily modified, proprietary commercial JDK engineered explicitly for high-throughput and ultra-low latency workloads. It utilizes the proprietary “C4” garbage collector (Continuously Concurrent Compacting Collector), which completely eliminates the random Stop-The-World freezes that plague standard Java setups so often.
Temurin provides long-term support (LTS) for major Java versions free of charge, long after Oracle stops public updates. It’s heavily tested. Every Temurin build has to pass the AQAvit quality test suite, which runs over 200,000 integration, performance, and security tests.
openjdk.org, GNU General Public License, version 2, with the Classpath Exception
Oracle, Oracle Technology Network License Agreement for Oracle Java SE