Install libnb-platform18-java-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libnb-platform18-java-doc
Description:
NetBeans Platform javadoc
NetBeans Platform is a set of modules, each providing their own APIs and working together or in a standalone mode. This package provides one master javadoc to all of them.
Homepage: http://netbeans.org/
Version: 8.1+dfsg1-7
Section: universe/doc