Maximum size of an Java array

Question

What is the maximum number of elements that an array in Java can contain?

Answer 1

Well, you can check it by using Integer.MAX_VALUE - 5.

public class Foo {
  public static void main(String[] args) {
    Object[] arr = new Object[Integer.MAX_VALUE - 4];
  }
}

It will throw an exception saying:

Exception in thread "main" java.lang.OutOfMemoryError:
  Requested array size exceeds VM limit

Answer 2

There are actually two limits. 

1. The maximum element indexable for the array and, 

2. The amount of memory available to your application. 

Depending on the amount of memory available and the amount used by other data structures, you may hit the memory limit before you reach the maximum addressable array element.