Java Basics-Object oriented

Java object-oriented three major features: encapsulation, inheritance, polymorphism;

Inheritance is an important means of implementing class reuse, in addition, it can be combined to achieve this reuse, compared with the use of inheritance to achieve reuse, sub-class objects can be directly assigned to the parent class variables, the variable is polymorphic, programming more flexible, and the use of composite relationships to achieve reuse does not have this flexibility.

Static is a special keyword that can be used to modify members such as methods, properties, and so on. The member surface of the static modifier is a common to this class, rather than a single instance of the property with that class;

Java Basics-Object oriented