Unpacking and boxing in Java

I. Concept of unpacking and boxing

Boxing: Converts the value of the base data type to the value of the reference type;

Unboxing: Converts the value of a reference type to a value of the base data type;

Two. Example Demo

public class Example19 {
    public static void Main (string[] args)
    {
        int a=20;
        Integer in=new integer (a);//Boxing
        int Sum=a+in.intvalue ();//Unpacking
        System.out.println (In.tostring ());//tostring () can be omitted
        SYSTEM.OUT.PRINTLN (sum);
    }
}

Three. JDK5.0 new features----automatic unpacking and boxing

1. Causes the basic data type and the reference data type to be mixed

int a=20;

Integer x=a;//Auto-boxing
Integer number=new integer (18);
int y=number;//Automatic Unpacking
int sum=x+y//Mixed operation

　　

Unpacking and boxing in Java