Integration of PowerMockRunner with JbpmJUnitTestCase

Issue

• There is a requirement to mock objects with PowerMockRunner with @RunWith(PowerMockRunner.class) and extending JbpmJUnitTestCase to test a BPMN2 process in jBPM5. The mocking is necessary since the jBPM5 makes use of a java class (methods of the java class are static).
  However, it is found that while running the Junit tests it gives an exception like following.

java.lang.IllegalStateException: Failed to transform class with name org.jbpm.test.JbpmJUnitTestCase. Reason: javassist.NotFoundException: org.h2.tools.DeleteDbFiles
                at org.powermock.core.classloader.MockClassLoader.loadMockClass(MockClassLoader.java:207)
                at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:145)
                at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:65)
                at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
                at java.lang.ClassLoader.defineClass1(Native Method)
                at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
                at java.lang.ClassLoader.defineClass(ClassLoader.java:643)
                at org.powermock.core.classloader.MockClassLoader.loadMockClass(MockClassLoader.java:210)
                at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:145)
                at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:65)
                at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
                at java.lang.Class.forName0(Native Method)
                at java.lang.Class.forName(Class.java:270)
...

How to fix this issue?