Java Basics-Object oriented

First, what is called object-oriented

　　Everything is object (to be corrected)

The three main characteristics of object-oriented

Encapsulation : You can hide implementation details and make your code modular.
inheritance : You can extend existing code modules (classes) to implement code reuse.
polymorphic: When inheriting and deriving, the class ensures that the interface is reused using the correct invocation of a property of an instance of any class in the family tree.
Polymorphic mechanisms in Java: overloading and rewriting

Pending update ...

Java Basics-Object oriented