Thread: Question about object passing to a method? My VOCAB sucks

In JAVA, When an object is passed to a method, the object’s data is copied into a method parameter.

If this is false can you tell me why?

Originally Posted by helloworld922

mmm, kind of. Technically everything is pass by value, but when you "pass an object" it's the objects address which gets passed by value.

ex.:

public static void doIt(int[] a)
{
    a = new int[1];
    a[0] = 5;
}
 
public static void doIt2(int[] a)
{
    a[0] = 4;
}
 
public static void main(String[] args)
{
    int[] val = new int[] {3};
    doIt(val);
    System.out.println(val[0]); // prints out 3
    doIt2(val);
    System.out.println(val[0]); // prints out 4
}

If java did pass a true pass by reference, the first print statement would print 5 instead of 3. However, since the memory address is passed by value, doIt() creates a new array and assigns a to point to that new array, leaving the original val reference unchanged. In doIt2(), a is initialized to refer to the same object as val, so making changes to a results in changes to the same object val points to since it's the same object.

The website you linked to points this distinction out.

you are talking to a 5th grader here. My vocab is that bad :<

Well dear tripline.....if you want to know that concept in-depth then i would recommend you Stanford University's chanel on youtube and in that you have to look for The Programming Methodologies by Mehron Sami.....All you need for that is a fast internet connection.
Hope that help's you in understanding the concept.

Regards,
Ashishkumar Haldar.