Discussion on Java Reference and Copy Instances

1. Concept

Reference copy is our commonly used object assignment. This method will not generate a new object, but will onlyadd a new object to the original object. Object reference , the two references still point to the same object.

2. Form

The default assignment method of Java objects is reference copying. For example, the process of object assignment in the following code is reference copying:

User user1 = new User();
User user2 = user1;

3. Example

class Son {
    String name;
    int age;
 
    public Son(String name, int age) {
        this.name = name;
        this.age = age;
    }
}
public class test {
    public static void main(String[] args) {
        Son s1 = new Son("son1", 12);
        Son s2 = s1;
        s1.age = 22;
        System.out.println(s1);
        System.out.println(s2);
        System.out.println("s1的age:" + s1.age);
        System.out.println("s2的age:" + s2.age);
        System.out.println("s1==s2" + (s1 == s2));//相等
    }
}

The output result is:

Son@135fbaa4
Son@135fbaa4
s1的age:22
s2的age:22
True

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