Java Applets A Java applet is a special kind of Java program that a browser enabled with Java technology can download from the internet and run. An applet is typically embedded inside a web page and ...

“The Java 7u21 release introduces changes to security messages related to running Java applets and applications,” Oracle said in a technical document that explains the changes.

Java applets may be re-enabled by clicking the region labeled "Inactive plug-in" on a web page. If no applets have been run for an extended period of time, the Java web plug-in will deactivate.