Question

Now I know that Java is purely passed-by-value, but are instance variables passed by reference?

Here’s what I mean (and I know this code is terrible, but it’s pseudo-code:

//Instance variables
private Object[] array = new Object[10];
array[4] = new Object[5];

//Private method
private Object ar(int x)
{
     return array[x];
}

//Inside Main or some other method
ar(4)[0] = "Foo";

Now, would the first slot on the array in array[4] be changed to “Foo” because array is an instance variable?

To Clarify:

I know that EVERYTHING is passed by value. But we are talking about calling things contained in instance variables, please focus on that. Thanks.

Answer 1

Yes, the first slot in array[4] will be changed to "Foo"

In Java, everything is passed by value. When passing objects, the reference to the object is passed by value. For your example, the object contained in array[4] is returned from the ar method.