code: public void testQueryVariablesNullNameArgument(){
    try {
      runtimeService.createProcessInstanceQuery().variableValueEquals(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
    try {
      runtimeService.createProcessInstanceQuery().variableValueNotEquals(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
    try {
      runtimeService.createProcessInstanceQuery().variableValueGreaterThan(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
    try {
      runtimeService.createProcessInstanceQuery().variableValueGreaterThanOrEqual(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
    try {
      runtimeService.createProcessInstanceQuery().variableValueLessThan(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
    try {
      runtimeService.createProcessInstanceQuery().variableValueLessThanOrEqual(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
    try {
      runtimeService.createProcessInstanceQuery().variableValueLike(null,"value");
      fail("Expected exception");
    }
   catch (  ActivitiIllegalArgumentException ae) {
      assertTextPresent("name is null",ae.getMessage());
    }
  }
  