Documentation is essentially the owner’s manual of a programming language. If you run into a problem while programming, visiting the documentation of your selected programming language can solve your problem.
At first, documentation might be difficult to navigate and understand. As you get better at programming, documentation become easier to read. Many professional programmers learn new programming languages by reading the documentation of a new language.
Here is a article that explains the art of reading documentation: https://sweetcode.io/art-reading-documentation/
Java Docs Homepage: https://docs.oracle.com/javase/7/docs/api/
Recommended Java Docs Link: https://docs.oracle.com/javase/7/docs/api/allclasses-noframe.html
This link is the recommended way of using Java Docs if you know the Java class name you want to read about. Here is how to use it: