Reference passing and value passing problems in Java

1. Refer to the value first:
String a = "God";//a stored in the stack God stores two objects in the head (heap)
String B=a;
A points to the God object in the heap
B=a; Note B also points to the God object in head; B=a only creates an object B
At this point the b= "other God" does not change the original value of B because the string class is the final decorated class, so when the assignment is made, a new other object is created in the team and then the B is directed to the other God object.

Let's take a data exchange operation.

public void swap (int a,int b) {
int temp=a;
A=b;
B=a;
System.out.println (A + "=" +b); 10 20
}
Main () {

int a=20;

b=10;
Swap (A, b);
System.out.println (A + "=" +b); 20 10

}
You can see that the A/b value in the Main method does not change, so he is the value passed

2. Reference delivery
void method (StringBuffer sb) {
Sb.append ("zzz");
}
Main () {
StringBuffer sb=new StringBuffer ("DD");
Method (SB);
System.out.println (Sb.tostring ());

}
You can see that the value of SB becomes ddzzz, a pair should be able to have many reference variables, but they are all working on the same object

Summary: Common data types such as (int, double) are value passes, and the objects that you define are reference passes.

Reference passing and value passing problems in Java