please explain

[vineet walia]

i am new in programing
anybody explain difference between call by value and call by reference with example ?
please also explain this program

class value
    {
       public int i=15;
    }


public class test {
      public static void main(String str [])
      {
	        test t =new test();
	          t.first();
	
	  }
	   public void first()
	   {
		   int i =5;
		   value v=new value();
		   v.i=25;
		   
		   second(v,i);
		   System.out.println(v.i);
	   }
	   public void second(value v, int i)
	   {
		   i=0;
		   v.i=20;
		   value val=new value();
		   v=val;
		   System.out.println(v.i+" "+i);
	   }
}

[HENRY: Added code tags]

[Himanshu Kansal]

Hello,

please post the code in proper tags.

Also, the code is not complete. Value class is missing

Regards

[vineet walia]

Himanshu Kansal wrote:Hello,

please post the code in proper tags.

Also, the code is not complete. Value class is missing

Regards

its working and its output is 15 0
20

[Himanshu Kansal]

Once you edited to put the Class Value's definition, you could have put in the CODE tags too.

[Himanshu Kansal]

Here is a line to clear all misunderstandings - Java is strictly Pass-by-Value.

If at some point you feel that a pass by reference has occured as in your code at second(v,i), you actually are passing the reference itself as a value. Hence any changes made to the reference are reflected in the actual arg.

I hope that you are clear that when we say,

 A a = new A();

"a" is only a reference that points to the object. Therefore, when you pass this "a" to a method, you actually pass a reference pointing to that object; which in turn is a pass by value because the reference is COPIED in the formal argument

Regards

[Mo Jay]

Also vineet walia , you need to quote your sources and say where you got this code from. This is one of the requirements when posting any piece of code here.

As of the output of the program, it is strait forward and I think that the guys (Himanshu) before me have done a good job describing the difference (if there is any) between pass-by-value and pass-by-reference.