title: Method of InjectMocks class return Null
body: <p>When running the JUnit test case with Mockito, I am getting null value returned from below <code>manager.managerLogString</code> method (method of <code>@InjectMocks</code> ArticleManager class).  </p>
  
  <pre><code>TestingString = manager.managerLogString();
  </code></pre>
  
  <p>At mean time, I am able to get correct "<code>UserInput</code>" value for below mockito verify method.</p>
  
  <pre><code>verify(user).setMyuserString("UserInput");
  </code></pre>
  
  <p>The complete code as captured below, appreciate if you could provide advice.  </p>
  
  <pre><code>package com;
  
  public class User {
    private String userString;
  
    public User() {}
  
    public void setMyuserString(String userString) {
       this.userString = userString;
    }
  
    public String logMyUserString() {
        return this.userString;
    }
  }
  </code></pre>
  
  <p>Article Manager:</p>
  
  <pre><code>package com;
  
  import javax.inject.Inject;
  
  public class ArticleManager{
  
    @Inject
    private User user;
  
    public String managerLogString() {
        return this.user.logMyUserString();
    }
  }
  </code></pre>
  
  <p>Tests:</p>
  
  <pre><code>package com;
  import static org.junit.Assert.*;
  import static org.mockito.Mockito.*;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.mockito.runners.MockitoJUnitRunner;
  import org.mockito.Captor;
  import org.mockito.InjectMocks;  
  import org.mockito.Mock;
  
  
  @RunWith(MockitoJUnitRunner.class)
  public class MockExample {
  @Mock User user;
  @InjectMocks private ArticleManager manager; 
  private String TestingString;
  
  @Test
  public void test() {
      user.setMyuserString("UserInput");
              // verify this mock class return correct value
      verify(user).setMyuserString("UserInput");
  
              // why this manager.managerLogString return null value ??
      TestingString = manager.managerLogString();
      System.out.println(TestingString);
  
      assertEquals("UserInput", TestingString);
  }
  }
  </code></pre>
  
  <p>With the advice from here, the code is working fine now.  The updated code as captured below.</p>
  
  <p>Updated code:</p>
  
  <pre><code>@Test
  public void test() {
      when(user.logMyUserString()).thenReturn("UserInput");
  
      TestingString = manager.managerLogString();
      verify(user).logMyUserString();
  
      System.out.println(TestingString);
  
      assertEquals("UserInput", TestingString);
  }
  </code></pre>