Pass by Reference in java

[rajujrk]

Hai All,

I have to set of Programs, Both deals with Object, One is with Predefined Object and another one is User Defined Object.

Program #1

class MyPass
{
    Integer i=new Integer(100);
    public void pass(){
 
        System.out.println(i);
        go(i);
        System.out.println(i);
    }
    public void go(Integer x){
        System.out.println(x);
        x=200;
        System.out.println(x);
    }
    public static void main(String arg[]){
        MyPass mp=new MyPass();
        mp.pass();
    }
}
 
OUTPUT:
 
100
100
200
100
 
 

Program #2

class Refer
{
    String name;
}
class PassByReference
{
    void calling()
    {
        Refer r=new Refer();
        r.name="abc";
        System.out.println("Before"+r.name);
        called(r);
        System.out.println("After"+r.name);
    }
    void called(Refer s)
    {
        s.name="xyz";
        System.out.println("Inside"+s.name);
    }
    public static void main(String args[])
    {
        PassByReference p=new PassByReference();
        p.calling();
    }
}
 
OUTPUT:
 
Beforeabc
Insidexyz
Afterxyz
 
 

In Prg #1 object value doesnt changed
In Prg #2 Change the value

[jkmyoung]

Sorry, what exactly is the question?

[rajujrk]

@jkmyoung
My Question is, Both Programs Pass the reference, but in first program the value doesn't changed, in second one it changed, what happening inside in this programs? how these two code executes?

[Dheeraj Joshi]

System.out.println("1" +i);
go(i);
System.out.println("4" +i);
 

i = 100.
Prints 100
Goes to go function
Prints 100
Makes x = 200
Prints 200
Comes out of loop
Prints 100

200 value of x is available inside the function go. Not in the function who is calling it.

Regards
Dheeraj Joshi

[Dheeraj Joshi]

In second example, You are passing the object to the function whose scope is at class level.

Regards
Dheeraj Joshi