title: java.lang.NullPointerException at org.powermock.api.mockito.internal.expectation.PowerMockitoStubberImpl.addAnswersForStubbing
body: <p><strong>Exception</strong></p>
  
  <pre><code>java.lang.NullPointerException 
      at org.powermock.api.mockito.internal.expectation.PowerMockitoStubberImpl.addAnswersForStubbing(PowerMockitoStubberImpl.java:67)
      at org.powermock.api.mockito.internal.expectation.PowerMockitoStubberImpl.when(PowerMockitoStubberImpl.java:42)
      at org.powermock.api.mockito.internal.expectation.PowerMockitoStubberImpl.when(PowerMockitoStubberImpl.java:105)
      at us.ny.state.ij.safeact.ask.facade.AmmoSellerKeeperFacadeBeanTest.setUp(FacadeBeanTest.java:84)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at 
  </code></pre>
  
  <p><strong>Code to mock</strong></p>
  
  <pre class="lang-java prettyprint-override"><code>BusinessServiceFactory serviceFactory = BusinessServiceFactory.getInstance();
  RegBusinessServiceImpl regCreateService = 
      serviceFactory.getRegBusinessService(adrEntityManager);
  </code></pre>
  
  <p><strong>Test Code</strong></p>
  
  <pre class="lang-java prettyprint-override"><code>@RunWith(PowerMockRunner.class)
  @PrepareForTest({ BusinessServiceFactory.class})
  public class FacadeBeanTest {
  
      @Before
      public void setUp() throws Exception {
          AmmoSellerRegBusinessServiceImpl  mockRegBusinessServiceImpl 
              = mock(AmmoSellerRegBusinessServiceImpl.class);
          PowerMockito.doReturn(mockRegBusinessServiceImpl)
              .when(BusinessServiceFactory.class,"getRegBusinessService",
              (mockEntityManager)); //--- line 84 null pointer exception
      }
  }
  </code></pre>
  
  <p>I can't understand why I'm seeing the exception. I'd appreciate any suggestions.</p>