code: @Deployment(resources={"org/activiti/engine/test/api/oneTaskProcess.bpmn20.xml"}) public void testQueryStringVariable(){
    Map<String,Object> vars=new HashMap<String,Object>();
    vars.put("stringVar","abcdef");
    ProcessInstance processInstance1=runtimeService.startProcessInstanceByKey("oneTaskProcess",vars);
    vars=new HashMap<String,Object>();
    vars.put("stringVar","abcdef");
    vars.put("stringVar2","ghijkl");
    ProcessInstance processInstance2=runtimeService.startProcessInstanceByKey("oneTaskProcess",vars);
    vars=new HashMap<String,Object>();
    vars.put("stringVar","azerty");
    ProcessInstance processInstance3=runtimeService.startProcessInstanceByKey("oneTaskProcess",vars);
    ExecutionQuery query=runtimeService.createExecutionQuery().variableValueEquals("stringVar","abcdef");
    List<Execution> executions=query.list();
    assertNotNull(executions);
    assertEquals(2,executions.size());
    query=runtimeService.createExecutionQuery().variableValueEquals("stringVar","abcdef").variableValueEquals("stringVar2","ghijkl");
    Execution execution=query.singleResult();
    assertNotNull(execution);
    assertEquals(processInstance2.getId(),execution.getId());
    execution=runtimeService.createExecutionQuery().variableValueNotEquals("stringVar","abcdef").singleResult();
    assertNotNull(execution);
    assertEquals(processInstance3.getId(),execution.getId());
    execution=runtimeService.createExecutionQuery().variableValueGreaterThan("stringVar","abcdef").singleResult();
    assertNotNull(execution);
    assertEquals(processInstance3.getId(),execution.getId());
    execution=runtimeService.createExecutionQuery().variableValueGreaterThan("stringVar","z").singleResult();
    assertNull(execution);
    assertEquals(3,runtimeService.createExecutionQuery().variableValueGreaterThanOrEqual("stringVar","abcdef").count());
    assertEquals(0,runtimeService.createExecutionQuery().variableValueGreaterThanOrEqual("stringVar","z").count());
    executions=runtimeService.createExecutionQuery().variableValueLessThan("stringVar","abcdeg").list();
    assertEquals(2,executions.size());
    List<String> expectedIds=Arrays.asList(processInstance1.getId(),processInstance2.getId());
    List<String> ids=new ArrayList<String>(Arrays.asList(executions.get(0).getId(),executions.get(1).getId()));
    ids.removeAll(expectedIds);
    assertTrue(ids.isEmpty());
    assertEquals(0,runtimeService.createExecutionQuery().variableValueLessThan("stringVar","abcdef").count());
    assertEquals(3,runtimeService.createExecutionQuery().variableValueLessThanOrEqual("stringVar","z").count());
    executions=runtimeService.createExecutionQuery().variableValueLessThanOrEqual("stringVar","abcdef").list();
    assertEquals(2,executions.size());
    expectedIds=Arrays.asList(processInstance1.getId(),processInstance2.getId());
    ids=new ArrayList<String>(Arrays.asList(executions.get(0).getId(),executions.get(1).getId()));
    ids.removeAll(expectedIds);
    assertTrue(ids.isEmpty());
    assertEquals(3,runtimeService.createExecutionQuery().variableValueLessThanOrEqual("stringVar","z").count());
    assertEquals(0,runtimeService.createExecutionQuery().variableValueLessThanOrEqual("stringVar","aa").count());
    execution=runtimeService.createExecutionQuery().variableValueLike("stringVar","azert%").singleResult();
    assertNotNull(execution);
    assertEquals(processInstance3.getId(),execution.getId());
    execution=runtimeService.createExecutionQuery().variableValueLike("stringVar","%y").singleResult();
    assertNotNull(execution);
    assertEquals(processInstance3.getId(),execution.getId());
    execution=runtimeService.createExecutionQuery().variableValueLike("stringVar","%zer%").singleResult();
    assertNotNull(execution);
    assertEquals(processInstance3.getId(),execution.getId());
    assertEquals(3,runtimeService.createExecutionQuery().variableValueLike("stringVar","a%").count());
    assertEquals(0,runtimeService.createExecutionQuery().variableValueLike("stringVar","%x%").count());
    execution=runtimeService.createExecutionQuery().variableValueEquals("azerty").singleResult();
    assertNotNull(execution);
    assertEquals(processInstance3.getId(),execution.getId());
    executions=runtimeService.createExecutionQuery().variableValueEquals("abcdef").list();
    assertEquals(2,executions.size());
    expectedIds=Arrays.asList(processInstance1.getId(),processInstance2.getId());
    ids=new ArrayList<String>(Arrays.asList(executions.get(0).getId(),executions.get(1).getId()));
    ids.removeAll(expectedIds);
    assertTrue(ids.isEmpty());
    execution=runtimeService.createExecutionQuery().variableValueEquals("notmatchinganyvalues").singleResult();
    assertNull(execution);
    runtimeService.deleteProcessInstance(processInstance1.getId(),"test");
    runtimeService.deleteProcessInstance(processInstance2.getId(),"test");
    runtimeService.deleteProcessInstance(processInstance3.getId(),"test");
  }
  