Off-hand I think that there were at least 7 forks/implementations out there. Oracle/Sun, Oracle's Graal, IBM, OpenJDK, Amazon Coretto, Twitter's fork, and Azul. There's also a GNU effort but I don't think that really went very far. I think there's probably a few others that aren't publicly well known for trading firms, etc.

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brabel 4 days ago | parent | next [-]

> there were at least 7 forks/implementations out there

There are 17 listed on SDKMAN's website: https://sdkman.io/jdks

> OpenJDK

As far as I know, all other distributions of the JDK are forks of OpenJDK. Would love to know if there's any that isn't.

	▲	pjmlp 4 days ago \| parent [-]
		Commercial embedded vendors with RTOS capabilities, https://www.ptc.com/en/products/developer-tools/perc https://www.aicas.com/products-services/jamaicavm/ JikesRVM (https://www.jikesrvm.org) no longer active, but it was its own thing. Then you have Azul Zing and OpenJ9, which use parts of OpenJDK for the standard library part, but the foundations are their own thing. https://www.azul.com/products/prime/ https://developer.ibm.com/components/open-j9/ Then you have that mobile OS, which isn't really JVM compliant implementation, but it is close enough for many workloads and libraries to work on top of it.

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throwaway2037 4 days ago | parent | prev | next [-]

JetBrains also has a fork that they use to run some (all?) of their IDEs, such as CLion (C/C++) and IntelliJ (Java). As I understand, it has many fixes for HiDPI environments when painting GUI widgets (Swing, etc.).

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_glass 4 days ago | parent | prev [-]

SAP has also a fork: https://github.com/SAP/SapMachine.