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Creating and Using Extensions

Any set of packages or classes can easily be made to play the role of an extension. The first step in turning a set of classes into an extension is to bundle them in a JAR file. Once that's done, you can turn the software into an extension in two ways:

This lesson shows you how the extension mechanism works by using a simple "toy" extension as an example. The next lesson, Setting Extension Security Privileges, uses the same extension to show how the Java platform controls the security permissions that are granted to extensions.

Installed Extensions

In this section, you'll create a simple installed extension and see how extension software is treated as part of the platform by the runtime environment.

Download Extensions

This section will show you how modify a JAR file's manifest so that the JAR-bundled software can make use of download extensions.

Understanding Extension Class Loading

This section is a short detour that summarizes the 1.2 platform's new delegation model for loading classes, and shows how it relates to loading classes in extensions.


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