title: PowerMock NoClassDefFoundError
body: <p>I have some simple classes I'm using to see if I can get <code>powermock</code> to work:</p>
  
  <pre><code>import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.powermock.api.easymock.PowerMock;
  import org.powermock.core.classloader.annotations.PrepareForTest;
  import org.powermock.modules.junit4.PowerMockRunner;
  
  @RunWith(PowerMockRunner.class)
  @PrepareForTest(Foo.class)
  public class FooTest
  {
      @Test
      public void testFoobar(){
          Foo test = PowerMock.createPartialMock(Foo.class, "foobar");
          PowerMock.replay(test);
      }
  }
  </code></pre>
  
  <p>and</p>
  
  <pre><code>public class Foo
  {
      public String foobar(String aString){
          return aString + " blah";
      }
  }
  </code></pre>
  
  <p>When I try to run this unit test, it tells me:</p>
  
  <pre><code>java.lang.NoClassDefFoundError: org/easymock/classextension/internal/ClassProxyFactory$MockMethodInterceptor
  ...
  </code></pre>
  
  <p>I have no idea why its doing this. Please help.</p>