The Java Extension Mechanism

JDK 1.2 Contents

Extensions are packages of Java classes (and any associated native code) that application developers can use to extend the functionality of the core platform. The extension mechanism allows the Java virtual machine (VM) to use the extension classes in much the same way as the VM uses the system classes. The extension mechanism also provides a way for needed extensions to be retrieved from specified URLs when they are not already installed in the JDK or JRE.

• Overview - What extensions are and how to turn Java packages into extensions.

• Specification - The specification for the Java extension mechanism.

The following classes play a role in the extension mechanism:

• java.lang.ClassLoader
• java.lang.Package
• java.lang.Thread
• java.net.JarURLConnection
• java.net.URLClassLoader
• java.security.SecureClassLoader

FAQ

• FAQ - Answers to frequently asked questions about extensions.

Located on the Java Software website:

• The Java Extension Mechanism trail of the Java Tutorial.

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