What steps will reproduce the problem?

Try to use this

 <dependency>
       <groupId>org.mockito</groupId>
        <artifactId>mockito-core</artifactId>
        <version>${mockito.version}</version>
        <scope>test</scope>
        <exclusions>
          <exclusion>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
          </exclusion>
        </exclusions>
      </dependency>
      <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-core</artifactId>
        <version>${powermock.version}</version>
        <scope>test</scope>
      </dependency>
      <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-api-mockito2</artifactId>
        <version>${powermock.version}</version>
        <scope>test</scope>
        <exclusions>
          <exclusion>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-all</artifactId>
          </exclusion>
          <exclusion>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
          </exclusion>
        </exclusions>
      </dependency>

with

<powermock.version>1.6.6</powermock.version>
<mockito.version>2.2.21</mockito.version>

java.lang.IllegalAccessError: tried to access method org.mockito.internal.util.ObjectMethodsGuru.()V from class org.powermock.api.mockito.repackaged.MethodInterceptorFilter
at org.powermock.api.mockito.repackaged.MethodInterceptorFilter.(MethodInterceptorFilter.java:32)
at org.powermock.api.mockito.repackaged.CglibMockMaker.createMock(CglibMockMaker.java:27)
at org.powermock.api.mockito.internal.mockmaker.PowerMockMaker.createMock(PowerMockMaker.java:48)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:35)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:63)
at org.mockito.Mockito.mock(Mockito.java:1632)
at org.mockito.Mockito.mock(Mockito.java:1545)
at com.siemens.spice.hscm.integration.configui.ccm.ConfigUiCcmApplicationManagerTest.missingChild(ConfigUiCcmApplicationManagerTest.java:145)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:86)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:646)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:823)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1131)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:129)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:112)
at org.testng.TestRunner.privateRun(TestRunner.java:778)
at org.testng.TestRunner.run(TestRunner.java:632)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:366)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:361)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:319)
at org.testng.SuiteRunner.run(SuiteRunner.java:268)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1225)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1150)
at org.testng.TestNG.runSuites(TestNG.java:1075)
at org.testng.TestNG.run(TestNG.java:1047)
at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:132)
at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:236)
at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:81)

I guess this can not work because of the private constructor.