How to change value of Integer object ?

Question

I wrote a program:
public class Tester{
     public static void changeValue( Integer a, int b ){
          a.valueOf(b);
     public static void main( String[] args ){
          Integer a = new Integer(15);
          Tester.changeValue(a, 20);
          System.out.println(a); // It will print to screen the value 15, but i want it is 20.
}Can you help me?????

Answer 1

Create a Value Object.
public class MyInteger {
    // The encapsulated property (required).
    private Integer value;
    // Always declare a default no-arg constructor if you have declared another constructors (javabean spec).
    public MyInteger() {
        // Default constructor, keep alive.
    // This constructor is here so that you don't need to call setValue() after default construction (optional).
    public MyInteger(Integer value) {
        this.value = value;
    // The getter of the encapsulated property (required).
    public Integer getValue() {
        return value;
    // The setter of the encapsulated property (required).
    public void setValue(Integer value) {
        this.value = value;
    // The string representation of this object which pleases reading in logs (optional).
    public String toString() {
        return "MyInteger[" + String.valueOf(value) + "]";
public class Tester {
    public static void changeValue(MyInteger myInteger, int b) {
        myInteger.setValue(new Integer(b));
    public static void main(String[] args) {
        MyInteger a = new MyInteger(new Integer(15));
        Tester.changeValue(a, 20);
        System.out.println(a);
}