Java would finally shed its Java Applet API under an OpenJDK proposal created December 4.
The JDK Enhancement Proposal notes that the API not only has been deprecated for removal for some time but is obsolete, because neither the current Java Development Kit (JDK) nor current web browsers support applets. Removal is slated for the Standard Edition of Java, although a specific JDK release not yet been designated.
The proposal cites multiple reasons for the APIs removal. First, the Applet API in JDK has no implementation, meaning there is no way to run an applet using the JDK. Second, browsers no longer support applets. Third, the appletviewer tool, which let developers test applets without a browser plugin, was removed in JDK 11, which was released in September 2018. Fourth, the Java Security Manager, which provides support for running applets by sandboxing untrusted downloaded code, will be removed with the JDK 24 release in March. Hence, there is no reason to keep the unusable and unused Applet API.
Java applets were first deprecated with JDK 9, which was released in September 2017. Applets essentially lost out to JavaScript and the web browser in web development. There also were security concerns about the applets.