title: HashSet is not sensitive to content of array?
body: <p>how can I make this code work such that when I change the content of the array, HashSet considers a different hashcode for it? Right now it prints "true". I want it to print true if and only if the elements are exactly the same.</p>
  
  <pre><code>HashSet&lt;int[][]&gt; x = new HashSet&lt;int[][]&gt;();
  int a[][] = {{1, 2}, {3, 4}};
  x.add(a);
  a[0][0] = 2;
  a[0][1] = 1;
  System.out.println(x.contains(a));
  </code></pre>