【Error】org.powermock.reflect.exceptions.FieldNotFoundException: Field 'fTestClass' was not found in

报错出现在eclipse IDE 单元测试下。

org.powermock.reflect.exceptions.FieldNotFoundException: Field 'fTestClass' was not found in class org.junit.internal.runners.MethodValidator.
at org.powermock.reflect.internal.WhiteboxImpl.getInternalState(WhiteboxImpl.java:581)
at org.powermock.reflect.Whitebox.getInternalState(Whitebox.java:308)
at org.powermock.modules.junit4.internal.impl.testcaseworkaround.PowerMockJUnit4MethodValidator.validate TestMethods(PowerMockJUnit4MethodValidator.java:79)
at org.powermock.modules.junit4.internal.impl.testcaseworkaround.PowerMockJUnit4MethodValidator.validate InstanceMethods(PowerMockJUnit4MethodValidator.java:49)
at org.junit.internal.runners.MethodValidator.validateMethodsForDefaultRunner(MethodValidator.java:51)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.validate(PowerMockJUnit44RunnerDelegateImpl.java:108)

网上给出的答案中，比较靠谱的是这个。

This is a bug that occurs when you use JUnit 4.12 and PowerMock < 1.6.1. The problem is solved in PowerMock 1.6.1. 

经过排查，我发现我所用的eclipse中，共存了两个Junit jar包，分别是4.12和4.10。如下图中，在maven中引入了4.10，额外在外部引入了4.12。删除了4.12后，问题得到解决。