title: Mockito: Trying to spy on method is calling the original method
body: <p>I'm using Mockito 1.9.0.  I want mock the behaviour for a single method of a class in a JUnit test, so I have</p>
  
  <pre><code>final MyClass myClassSpy = Mockito.spy(myInstance);
  Mockito.when(myClassSpy.method1()).thenReturn(myResults);
  </code></pre>
  
  <p>The problem is, in the second line, <code>myClassSpy.method1()</code> is actually getting called, resulting in an exception.  The only reason I'm using mocks is so that later, whenever <code>myClassSpy.method1()</code> is called, the real method won't be called and the <code>myResults</code> object will be returned.  </p>
  
  <p><code>MyClass</code> is an interface and <code>myInstance</code> is an implementation of that, if that matters.</p>
  
  <p>What do I need to do to correct this spying behaviour?</p>