How to watch help on java?

Question

Java

Hello everyone
Plz tell me how to watch help on classes in java? well, as in python, you open the interpreter, import the classes you need, and through the help function you can see the description of the class + the methods that it has \ that it supports:

import datetime
help(datetime)

And then every time going to oracle or rummaging through the Internet is not very convenient
in java, in ide it could be done somehow, unfortunately I forgot.
I use netbeans
thanks