As browsers have gained support for hardware-accelerated graphics thanks to the canvas technology (or specifically WebGL in the case of 3D graphics), as well as just-in-time compiled JavaScript, the speed difference has become less noticeable. Unlike JavaScript, Java applets had access to 3D hardware acceleration, making them well-suited for non-trivial, computation-intensive visualizations. Java applets run at very fast speeds and until 2011, they were many times faster than JavaScript. Java applets were usually written in Java, but other languages such as Jython, JRuby, Pascal, Scala, or Eiffel (via SmartEiffel) could be used as well. Java applets were deprecated since Java 9 in 2017.

Beginning in 2013, major web browsers began to phase out support for the underlying technology applets used to run, with applets becoming completely unable to be run by 2015вЂ“2017. Java applets were introduced in the first version of the Java language, which was released in 1995.

A Java applet could appear in a frame of the web page, a new application window, Sun's AppletViewer, or a stand-alone tool for testing applets. The user launched the Java applet from a web page, and the applet was then executed within a Java virtual machine (JVM) in a process separate from the web browser itself. Java applets were small applications written in the Java programming language, or another programming language that compiles to Java bytecode, and delivered to users in the form of Java bytecode. Demonstration of image processing using two dimensional Fourier transform

Java applet viewer source code