
OpenJDK is completely open source with a GNU General Public License. The main difference between OpenJdk and OracleJDK is licensing.

OpenJDK: Currently, the "OpenJDK" ) developed by Oracle, Java community, Red Hat, Azul Systems, IBM, Microsoft, Amazon, Apple, SAP, provides a free and open-source Java Platform Standard Edition (or Java SE or JDK) official reference implementation.

The Java Development Kit (JDK), officially named "Java Platform Standard Edition" or "Java SE", is needed for writing and running Java programs.
