How arrays and primitives are passed as parameters in java

[Mintoo Jaiswal]

How arrays and primitives are passed as parameters in java please explain in detail

[Stan James]

It's important to know all types are passed exactly the same way, by value. That means the JVM makes a copy of the parameter and the called method sees the copy.

If we pass a primitive things are pretty simple. The JVM makes a copy of the primitive and the argument contains the copy. If you change the value of an argument you change the copy, not the original.

int x = 3;
method(x);
print(x); -> displays 3
...
public void method(int i)
{
   i = 2; // changes the local copy
   print(i); -> displays 2
}

When we pass an object the JVM makes a copy of our variable and the method sees the copy. But what is our variable? It's a pointer to an object. So the method gets a copy of the pointer, not a copy of the object.

Point p = new Point(0,0);
method(p);
print(p.getX()); -> displays 2
...
public void method(Point point)
{
   point.setLocation(2,2);
}

Does that help?

[Mr. C Lamont Gilbert]

Its got to be in the FAQ by now.