OpenJDK is presently under GPL 2, with the "classpath exception" at the end: http://hg.openjdk.java.net/jdk9/jdk9/file/a08cbfc0e4ec/LICENSE http://hg.openjdk.ja

OpenJDK is presently under GPL 2, with the "classpath exception" at the end: http://hg.openjdk.java.net/jdk9/jdk9/file/a08cbfc0e4ec/LICENSE http://hg.openjdk.java.net/jdk9/jdk9/file/a08cbfc0e4ec/LICEN... At the time, though, I don't believe it was open source and OpenJDK originated as a cleanroom rewrite of it, and has since been integrated.