Next Generation Java applet plug-in technology

The applet is back!

In order to pass your program over the network, it is time to consider Java applet technology again. Next-generation Java plug-in technology runs applets in a different, more efficient and reliable way than in the past. Now you can get the following benefits:

Enhanced Reliability

Improved user Experience

Starting applets in the background

Built in JNLP support

command line arguments for each applet

Heap memory size, Java 2D API acceleration Options

An improved Java/javascript programming language integration

Improved Windows Vista support

Signed applets can now function in the protected mode of Internet Explorer

The next-generation Java plug-in provides a completely redesigned architecture that will appear in Java SE 6 Update 10. The plug-in provides powerful new features for applets running in Web browsers, which improve the reliability and functionality of the entire applet in a backward-compatible manner.

The most significant new feature of the next-generation Java plug-in is its built-in support for launching applets through JNLP files. Using the JNLP file format as a descriptor for the applet allows the applet to immediately reuse the JNLP extensions written for the Java Web start application.

New ways to implement applets

The new approach to executing applets is structurally similar to Java Web start technology, but is more tightly integrated with browsers. Instead of running in a JVM in a Web browser, the applet starts a separate JVM process to run the applet. By default, only one JVM will be started, but you can also start multiple JVMs, and you can set command-line arguments for each applet, so you can affect the size of the heap memory or other requirements.

Figure 1. Applet Architecture

In the above illustration, the cloud represents a JVM instance. Within the browser there is a small, headless JVM that is used to manage connections between one or more client JVMs, which run applets. In the figure, Duke represents the applet. One JVM instance runs two applets, and the other runs an applet.

The applet launches directly from the JNLP file and uses the same JNLP file as the descriptor file used by the Java Web start software, and allows for more powerful parameters than the typical "archive", "Code" and "Cache_archive".