title: how to handle CriteriaBuilder and predicates in junit mockito testcase
body: <pre><code>        Impl.java
          ------------------------------------------------------------------
           public List&lt;SearchDTO&gt; findByCriteria(SearchCriteriaDTO SearchCriteriaDTO) {
                  CriteriaBuilder builder = entityManager.getCriteriaBuilder();
                  CriteriaQuery&lt;Search&gt; query = builder.createQuery(Search.class);
                  Root&lt;Search&gt; repls = query.from(Search.class);
  </code></pre>
  
  <p>final int QUERY_LIMIT = Integer.parseInt(queryLimit);</p>
  
  <pre><code>    List&lt;UUID&gt; statusIds = SearchCriteriaDTO.getStatusIds();
      if (statusIds != null &amp;&amp; !statusIds.isEmpty()) {
          predicates.add(builder.and(repl.get("statusId").in(statusIds)));
      }
          -----------------------------
  </code></pre>
  
  <p>below is the test class for impl class.</p>
  
  <pre><code>        impltest.java
          ---------------------------
  //mocking the services.
       @Mock
          private SearchMapper SearchMapper;
          @Mock
          private SearchRepository SearchRepository;
  
          @Mock
          private CriteriaBuilder criteriaBuilder;
  
          @Mock
          private Root root;
  
          @Mock
          private EntityManager entityManager;
          @Rule
          public ExpectedException thrown = ExpectedException.none();
  
          @Mock
          CriteriaQuery&lt;Search&gt;  criteriaQuery;
  
          @Mock
          Root&lt;UUID&gt; statusId;
  
          @Mock
          Path&lt;String&gt; path;
  
          @Mock
          Expression expr;
  
          @Mock
          Predicate predicate;
  
          @Mock
          TypedQuery&lt;Member&gt; querymem;
  
          @Mock
          Root&lt;Search&gt; rSearchRootMock;
  
          @InjectMocks
  
          private SearchServiceImpl SearchService;
  
        @Value("${query.limit}")
  
          String queryLimit;
  
          @Before
          public void init() {
  
              MockitoAnnotations.initMocks(SearchService);
              SearchRootMock = mock(Root.class);
          }
            @Test
              public void test_findby_criteria() {
          hen(entityManager.getCriteriaBuilder()).thenReturn(criteriaBuilder); when(criteriaBuilder.createQuery(Search.class)).thenReturn(criteriaQuery);
                  when(criteriaQuery.from(Search.class)).thenReturn(SearchRootMock);
                  Path statusIdMock = mock(Path.class);
  
                  //when(Integer.parseInt(queryLimit)).thenReturn(1);
                  String status = "statusId";
  
                  Expression&lt;String&gt; doublePath = root.get(status);
                  when(root.get((status))).thenReturn((Path) doublePath);
                  when(criteriaBuilder.upper(root.&lt;String&gt;get(status))).thenReturn(expr);
                  when(criteriaBuilder.equal(expr,status.toUpperCase())).thenReturn(predicate);
  
                  when(root.get("statusId")).thenReturn(path);
                  when(this.SearchService.findByCriteria(SearchCriteriaDTO)).thenReturn(Searches);
  
          here i am trying to mock the predicate but getting null point exception due to root.get("statusId").
          please let me know how to mock it.
  </code></pre>
  
  <p>here are the issues</p>
  
  <p>how to handle and mock the  @Value("${query.limit}") where i am reading limit from application properties file.
  getting null point exception in predicate line.
   predicates.add(builder.and(repl.get("statusId").in(statusIds)));</p>
  
  <pre><code>     not able to map the column name here for repl.get("statusId") where getting null.
  </code></pre>
  
  <p>please help me to solve this problem.Thanks</p>
  
  <p>below is the error
  java.lang.NumberFormatException: For input string: "${query.limit}"</p>
  
  <pre><code>at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
  at java.lang.Integer.parseInt(Integer.java:569)
  at java.lang.Integer.parseInt(Integer.java:615)
  at com.capturerx.cumulus4.replenishment.impl.ReplenishmentSearchServiceImplTest.test_findby_criteria_for_success(ReplenishmentSearchServiceImplTest.java:118)
  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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
  at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
  at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
  at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
  at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
  at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
  at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
  at org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:239)
  at org.junit.rules.RunRules.evaluate(RunRules.java:20)
  at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
  at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
  at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
  at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
  at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
  at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
  at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
  at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
  at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
  at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
  at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
  at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
  at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
  at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
  at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
  at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
  at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
  at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
  </code></pre>
  
  <hr>
  
  <p>getting java.lang.NullPointerException at line
  query.select(replenishments).where(predicates.toArray(new Predicate[predicates.size()]));</p>