title: PowerMock(with mockito) simple unit test error
body: <p>I am using <a href="https://code.google.com/p/powermock/wiki/MockitoUsage" rel="nofollow">Mockito + PowerMock</a> to write a simple unit test for the following singleton class:</p>
  
  <pre><code>public class MyService {
     private static MyService service;
     private List&lt;School&gt; schoolList;   
  
     private MyService(){
        // test case error complains here!
        School school = new School(); 
        schoolList.add(school);
     }
  
     public static Singleton getInstance( ) {
        return service;
     }
  
     protected static void printSchool( ) {
        School school = schoolList.get(0);
        print(school);
     }
  }
  </code></pre>
  
  <p>My Test case:</p>
  
  <pre><code>@RunWith(PowerMockRunner.class)
  public class MyServiceTest {
  
    @PrepareForTest({MyService.class})
    @Test
    public void testPrintSchool() {
       // enable mock static function
       PowerMockito.mockStatic(MyService.class);
  
       MyService mockService = PowerMockito.mock(MyService.class);
       PowerMockito.when(MyService.getInstance())
                    .thenReturn(mockService);
    }
  
  }
  </code></pre>
  
  <p>I run my test, but got the following error:</p>
  
  <pre><code>java.lang.RuntimeException: Invoking the beforeTestMethod method on PowerMock test listener org.powermock.api.extension.listener.AnnotationEnabler@3ab19451 failed.
      at com.xyz.MyService.&lt;init&gt;(MyService.java:12)
      at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
      at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
      at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
      at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
      at org.mockito.internal.util.reflection.FieldInitializer$ParameterizedConstructorInstantiator.instantiate(FieldInitializer.java:257)
      at org.mockito.internal.util.reflection.FieldInitializer.acquireFieldInstance(FieldInitializer.java:124)
      at org.mockito.internal.util.reflection.FieldInitializer.initialize(FieldInitializer.java:86)
      at org.mockito.internal.configuration.injection.ConstructorInjection.processInjection(ConstructorInjection.java:52)
  ...
  </code></pre>
  
  <p>As you can see, the error complains about <code>MyService.java:12</code> line 12, that is the line <code>School school = new School();</code>  in <code>MyService</code> constructor.</p>
  
  <p>Why I get this error, how to get rid of it?</p>