title: JsonMappingException: No suitable constructor found
body: <p>I am implementing a firebase example as given in their documentations. I am facing this error:</p>
  
  <blockquote>
    <p>com.fasterxml.jackson.databind.JsonMappingException: No suitable constructor found for type [simple type, class com.XYZ.$BlogPost]: can not instantiate from JSON object (need to add/enable type information?)</p>
  </blockquote>
  
  <p>Here is my code:</p>
  
  <pre><code>    public class MainActivity extends Activity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_user);
          Firebase.setAndroidContext(this);
      }
  
      @Override
      protected void onStart() {
          super.onStart();
          // Get a reference to our posts
          Firebase ref = new Firebase("https://docs-examples.firebaseio.com/web/saving-data/fireblog/posts");
          // Attach an listener to read the data at our posts reference
          ref.addValueEventListener(new ValueEventListener() {
              @Override
              public void onDataChange(DataSnapshot snapshot) {
                  System.out.println("There are " + snapshot.getChildrenCount() + " blog posts");
                  for (DataSnapshot postSnapshot: snapshot.getChildren()) {
                      BlogPost post = postSnapshot.getValue(BlogPost.class);
                      System.out.println(post.getAuthor() + " - " + post.getTitle());
                  }
              }
              @Override
              public void onCancelled(FirebaseError firebaseError) {
                  System.out.println("The read failed: " + firebaseError.getMessage());
              }
          });
      }
  public class BlogPost {
          private String author;
          private String title;
          public BlogPost() {
              // empty default constructor, necessary for Firebase to be able to deserialize blog posts
          }
          public String getAuthor() {
              return author;
          }
          public String getTitle() {
              return title;
          }
      }
  }
  </code></pre>
  
  <p>I have gone through many questions on the same thing saying to include empty constructor necessary to deserialize the JSON. I have included that but still I am not able to resolve the issue. This is the JSON I am trying to deserialize: </p>
  
  <pre><code>{  
     "-JRHTHaIs-jNPLXOQivY":{  
        "author":"gracehop",
        "title":"Announcing COBOL, a New Programming Language"
     },
     "-JRHTHaKuITFIhnj02kE":{  
        "author":"alanisawesome",
        "title":"The Turing Machine"
     }
  }
  </code></pre>
  
  <p>I don't know what I am missing in my code. Any help regrading this is appreciated.</p>