Day seventh (object-oriented)

(1) This: is the corresponding reference of the current class. In simple terms, it represents an object of the current class.

This scenario: Resolves a local variable hidden member variable.

(2) Construction method:

Function: Initializes the data for the object.

Format: 1. The method name is the same as the class name; 2. No return value type, not even void; 3. No specific return value.

Class Student () {

　　　　　　Public Student () {

System.out.println ("This is the construction method");

}

Note: If we do not give a construction method, the system will automatically provide a non-parametric construction method.

Student s = new Student (); What does it do in memory:

A: Load the Student.class file into memory;

B: In the stack memory to the s variable to open up a space;

C: In the memory for the student object to apply for a space;

D: Default initialization of member variables;

E: Display initialization of the member variables;

F: Initialize the member variables by constructing the method;

G: Data initialization is complete, then the address value of the heap memory is assigned to the stack memory s variable.

(3) Static: static.

Features: (It can modify member variables and can also modify member methods)

A: Loads as the class loads.

B: Precedence over object existence.

C: Shared by class on all objects.

D: Can be called by object name, or by class name.

(4) Private:

A: Private meaning, can modify member variable and member method
B: Features: Members who have been modified by private can only be accessed in this class
Application of C:private:
To write a class later:
Give all the member variables to private.
provides the corresponding getxxx ()/setxxx () method

(5) The Main method is static:
Public: Maximum Permissions
Static: Do not create object calls
void: Return value does not make sense to the JVM
Main: is a common name.
String[] args: Can receive data, flexibility of the provider
Format: Java maindemo Hello World Java
Java Maindemo 10 20 30

　　

Day seventh (object-oriented)