Mostly morden browser has stop support Java plugins, so you can't run Java applet on browser.

Temporary way :

  • run in IE or Safari
  • run in an old Firefox (version 23)

And what if old java applet can't be runned on Java 8 because of weak signature algorithm. Try this

  • Open file :
    • In MacOS, located in /Library/Java/JavaVirtualMachines/jdk[jdk-version].jdk/Contents/Home/jre/lib/security
    • In Windows, located in C:\Program File x86\Java\jre\lib\security
  • Comment this line, jdk.certpath.disabledAlgorithms=MD2, MD5, RSA keySize < 1024
  • Rerun applet