title: Calling Java varargs method with single null argument?
body: <p>If I have a vararg Java method <code>foo(Object ...arg)</code> and I call <code>foo(null, null)</code>, I have both <code>arg[0]</code> and <code>arg[1]</code> as <code>null</code>s. But if I call <code>foo(null)</code>, <code>arg</code> itself is null. Why is this happening? </p>
  
  <p>How should I call <code>foo</code> such that <code>foo.length == 1 &amp;&amp; foo[0] == null</code> is <code>true</code>?</p>