Use of constructors

package oop.Demo01;

// There is only one specification for a project main Method 
public class Application {
    
    public static void main(String[] args) {
    

        //new  key word   An object is instantiated 
        Person person = new Person(" skin ",12);
        System.out.println(person.name+person.age);
    }
}

package oop.Demo01;

public class Person {
    
    // Even if a class doesn't write anything , It also has a way 
    // The definition constructor of the display 

    String name;
    int age;

    /* Default constructor */
    // No arguments structure 
    // Instantiate the initial value 
    //1. Use new keyword , The essence is to call the constructor again 
    //2. Used to initialize values 
    public Person(){
    
        this.name = " Pixiaopi ";// Define the initial value （ There can be no ）
    }

    /* heavy load */
    // There are parametric structures : Once a parametric construct is defined , A parameterless construct must display the definition 
    public Person(String test,int age){
    
        this.name = test;
        this.age = age;
    }

}

/*  Constructors ： 1. Same as class name  2. no return value   effect ： 1.new, The essence is calling constructor  2. Initialize the value of the object   Be careful ： 1. After defining a parametric construct , If you want to use a nonparametric construct , The definition of the display is a parameterless construct  idea Shortcut key ：Alt + Insert （ Quick build construction ） this. =  The current class  */