How can i read about all classes in java ... What are the commands? And how can i see these classes as a webpage document ? Anyb

Answer 1

Just do a search on Google. Plenty of documentation on it.

http://docs.oracle.com/javase/8/
http://docs.oracle.com/javase/8/docs/api/index.html

^Poke around through their site. References a lot of stuff for you. Afterward, just do a search, there is endless resources on this subject.

Answer 2

Command is a design pattern. In Java you can do it with the Statement class or with a lambda expression, if that is what you're looking for.