OpenJDK is fully open source. Oracle JDK is built on OpenJDK but changes a few things here and there. * Oracle JDK has a different font rasteriser, maybe some

OpenJDK is fully open source. Oracle JDK is built on OpenJDK but changes a few things here and there. * Oracle JDK has a different font rasteriser, maybe some other bits like sound are different as well * Oracle JDK has Flight Recorder support (that's a commercial feature) * Oracle JDK supports both C1 and C2 JITs on ARM64, AFAIK an open source implementation of this is coming to OpenJDK 9, likely Oracle JDK will keep the existing implementation * Oracle JDK has additional commercial features like resource management [2] and application class data sharing OpenJDK vanilla is AFAIK not TCK-certified. However there are TCK-certified OpenJDK distributions [3]. TL;DR: OpenJDK is fully open source [1] https://docs.oracle.com/javacomponents/ https://docs.oracle.com/javacomponents/ [2] https://www.youtube.com/watch?v=0WZpmylHbFM&index=8&list=PLX8CzqL3ArzUo2dtMurvpUTAaujPMeuuU https://www.youtube.com/watch?v=0WZpmylHbFM&index=8&list=PLX... [3] https://www.azul.com/products/zulu/ https://www.azul.com/products/zulu/