JEP 504: Remove the Applet API

Summary

Remove the Applet API, which was deprecated for removal in JDK 17 (2021). It is obsolete because neither recent JDK releases nor current web browsers support applets.

Motivation

• Web browsers no longer support applets.

• The Applet API and the appletviewer tool were deprecated in JDK 9 via JEP 289 (2017), when web-browser vendors were already removing support for applets.

• The appletviewer tool, which allowed applets to be tested without using a browser, was removed in JDK 11 (2018). Since then, there has been no way to run applets using the JDK.

• The Applet API was deprecated for removal in JDK 17 via JEP 398 (2021).

• The Security Manager, a necessary support pillar for running applets by sandboxing untrusted code, was permanently disabled in JDK 24 via JEP 486 (2025).

There is no reason to keep the unused and unusable Applet API.

Description

We will remove the following elements of the Java Platform API:

• The entire java.applet package, consisting of:

  • java.applet.Applet
  • java.applet.AppletContext
  • java.applet.AppletStub
  • java.applet.AudioClip

• These additional classes:

  • java.beans.AppletInitializer
  • javax.swing.JApplet

• Any remaining API elements that reference the above classes and interfaces, including methods and fields in:

  • java.beans.Beans
  • javax.swing.RepaintManager

Testing

Any tests which rely on the Applet API will need to be updated, disabled, or removed. For jtreg-based tests in the main-line JDK repository, this work is almost complete. Most such tests merely use the Applet API for convenience; few of them explicitly test the API.

Risks and Assumptions

• Given that it is largely unusable, there are no substantial risks to user applications in removing the Applet API.

• Applications that still use the Applet API will either stay on older releases or will migrate to some other API. In cases where the Applet class serves as a user-interface container component, the AWT API provides several alternatives.

• The return type of the getContent() methods of the java.net.URL and java.net.URLConnection classes is java.lang.Object. The precise type of the returned object depends upon the type of the content; when using these methods, the caller must test the type of the returned object in order to make use of it.

  Historically, these getContent() methods have returned instances of java.applet.AudioClip when the content is audio data recognized by the JDK’s built-in content handlers. With the removal of the Applet API, this will no longer be possible and instances of some other type will be returned. Code which casts the result of calling these methods to AudioClip will no longer compile or run, and will require adjustment.

• The jtreg tool references the Applet API, so it must be built using a JDK that still supports applets. This is required anyway, however, since jtreg must be able to test JDK release trains older than what the current javac compiler supports. At run time, jtreg only loads the Applet API when encountering an applet-based test, so a single jtreg build can support older JDK builds as well as newer builds which omit the Applet API.