Java simple summary class and object-14 days study notes

Class and object

• A class is a template is an abstract, an object is a concrete instance

method

• Define, call

Object reference

• In addition to the 8 types of reference types, we can all be called reference types
• Objects are manipulated by reference: stack ------ "heap (address)

Object properties

• Attributes are generally called fields, also called member variables
• Default initialization

​ Number 0 or 0.0

​ char ： u0000

​ boolean ： false

​ Reference type: null

Definition of attributes

Modifier attribute type attribute name = attribute value

int a = 0；

Creation and use of objects

1. The new keyword must be used to create the object, the constructor Person xiaoHuangRen = new Person();

2. The attributes of the object xiaoHuangRen.name;

   ​ xiaoHuangRen.age;

   Object method xiaoHuangRen.sleep();

class

Static properties

Dynamic approach