how install icedtea6-plugin ubuntu

ubuntu

icedtea6-plugin

Web browser plugin to execute java applets (dependency package)
http://icedtea.classpath.org/wiki/IcedTea-Web
Install sudo apt install icedtea6-plugin
Description:

Icedteaplugin is a web browser plugin to execute java applets, supporting liveconnect/javascript. it is targeted for xulrunner-1.9 and compatible browsers that support the npapi.

this is a dependency package, it can be safely removed after upgrade.