Authenticate with Java Applet method is the original authentication method for the system. This method requires Java Runtime Environment (JRE) installed on the system, and Java Applet Plugin installed into the browser. The Java Applet Plugin has to be configured to use the installed JRE. Many newer versions of major browsers may not support Java Applet Plugin.
Authenticate with Java Web Start requires Java Runtime Environment (JRE) installed on the system, with Web Start launcher (javaws) configured to process downloaded JNLP files, either by file extension or by file content type. These configuration steps are performed by standard JRE installation process. Java Applet Plugin is NOT required.