Where can I find a description of java classes?

Question

Java

Hello everyone
Tell me, plz, where can I find an INTERNATIONAL (if not for "fools", but at least detailed) description of classes in the JAVA API? (expanded is understood as a description of the internals, a description of the relationship \ interaction \ dependencies, what it probes, what where you need to click / put so that it just takes off :))
on the oracle site (docs.oracle.com/javase/7/docs/api) there is something that simply describes fields-methods-classes, nothing more. What is needed is the nature of the interaction.
The question arose because I am learning java, writing a test program using the javax.sound.midi.* libraries
and, despite the description of the details of the library (classes, methods, fields, etc.), the nature of the interaction, what goes where and what touches is incomprehensible (without a book with a test case very hard to understand)
Thanks

Answer 1

In IntelliJ IDEA, the cursor is on the class/method of interest and Ctrl+ B== is all you need to get a deep understanding of the internal structure.

Answer 2

There is a Java tutorial . About the sound a little written here