static

public class Test {
static class IntA{
private int a;
public IntA(int a){
this.a=a;
}
public int getA() {
return a;
}
public void setA(int a) {
this.a = a;
}
}
public static void change(int a){
a=3;
}
public static void change(IntA a){
a.setA(3);
}
public static void changeRef(IntA a){
a = new IntA(9);
}


public static void main(String args[]) {
int a = 2;

//堆栈
change(a);
//2
System.out.println(a);
IntA ia = new IntA(5);
change(ia);
//3
System.out.println(ia.getA());
changeRef(ia);
//3
System.out.println(ia.getA());
}