C header Files(In the include/ subdirectory) Header files that support native-code programming using the Java Native Interface, the JVM Tool Interface, and other functionality of the Javaplatform.Sample Code(In the sample subdirectory) Samples, with source code, of programming for certain Java API's.These include examples that use Swing and other Java Foundation Classes, and the Java Platform Debugger Architecture. Demo Applets and Applications(In the demo/ subdirectory) Examples, with source code, of programming for the Javaplatform.Additional Libraries(In the lib/ subdirectory) Additional class libraries and support files required by the development tools.Java Development Kit for Mac is a cross-platform SDK platform to provide specific implementation of Java SE, Java EE and Java ME platforms.