 Partly compatible open-source implementations have been developed for most, and in the case of Java, the main open-source implementation is by now very close to the commercial version.Since its first public release in 1996, the Java platform had not been open source, although the Java source code portion of the Java runtime was included in Java Development Kits (JDKs), on a purportedly "confidential" basis, despite it being freely downloadable by the general public in most countries.Sun later expanded this "confidential" source code access to include the full source code of the Java Runtime Environment via a separate program which was open to members of the public, and later made the source of the Java compiler "javac" available also.