Problems getting data on Android with Firebase

I just learned how to set up Firebase data on Android. I can write a db, but I cannot read and display it in my application. My application is very simple (it only has one main screen at the moment) and I don't care how the data is displayed on the page as I'm just learning - I'm currently trying to display it as text.

Here is my main java activity:

package com.example.ispotrachel.myapplication;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

import com.firebase.client.DataSnapshot;
import com.firebase.client.Firebase;
import com.firebase.client.FirebaseError;
import com.firebase.client.ValueEventListener;

import java.util.HashMap;
import java.util.Map;


public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Firebase.setAndroidContext(this);

    Firebase ref = new Firebase("https://blistering-torch-9015.firebaseio.com");

    class User {
        private int birthYear;
        private String fullName;

        public User() {
        }

        public User(String fullName, int birthYear) {
            this.fullName = fullName;
            this.birthYear = birthYear;
        }

        public long getBirthYear() {
            return birthYear;
        }

        public String getFullName() {
            return fullName;
        }
    }

     User user1 = new User("Name 1", 1982);
     User user2 = new User("Name 2", 1972);

     Firebase usersRef = ref.child("users");

     Map<String, User> users = new HashMap<String, User>();
     users.put("user1", user1);
     users.put("user 2", user2);

    usersRef.setValue(users);

    Firebase postRef = ref.child("posts");

    Map<String, String> post1 = new HashMap<String, String>();
    post1.put("author", "user1");
    post1.put("title", "Announcing COBOL, a New Programming Language");
    postRef.push().setValue(post1);

    Map<String, String> post2 = new HashMap<String, String>();
    post2.put("author", "user2");
    post2.put("title", "The Turing Machine");
    postRef.push().setValue(post2);
    ref.addValueEventListener(new ValueEventListener() {


    @Override
    public void onDataChange(DataSnapshot arg0) {
            //System.out.println(arg0.getValue());
            TextView textViewSample = (TextView) findViewById(R.id.sampleTextView);
            textViewSample.setText(arg0.getValue(String.class));
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            System.out.println("the read failed");
        }

    });
}}

      

        
        
        
      

    

Here is my activity_main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
 android:layout_height="match_parent"           android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity">


<TextView
    android:id="@+id/sampleTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world"/>


</LinearLayout>

      

        
        
        
      

    

When I run the application, it crashes. Here is the logcat error message:

12-27 12:15:02.678    1895-1895/com.example.ispotrachel.myapplication I/art﹕ Not late     enabling -Xcheck:jni (already on)
12-27 12:15:02.946    1895-1907/com.example.ispotrachel.myapplication I/art﹕ Background     sticky concurrent mark sweep GC freed 3867(286KB) AllocSpace objects, 0(0B) LOS objects, 11% free, 1009KB/1135KB, paused 2.595ms total 117.910ms
12-27 12:15:03.317    1895-1926/com.example.ispotrachel.myapplication D/OpenGLRenderer﹕ Render dirty regions requested: true
12-27 12:15:03.320    1895-1895/com.example.ispotrachel.myapplication D/﹕ HostConnection::get() New Host Connection established 0xa6667e80, tid 1895
12-27 12:15:03.327    1895-1895/com.example.ispotrachel.myapplication D/Atlas﹕ Validating map...
12-27 12:15:03.391    1895-1926/com.example.ispotrachel.myapplication D/﹕ HostConnection::get() New Host Connection established 0xa66ef3b0, tid 1926
12-27 12:15:03.405    1895-1926/com.example.ispotrachel.myapplication I/OpenGLRenderer﹕ Initialized EGL, version 1.4
12-27 12:15:03.422    1895-1926/com.example.ispotrachel.myapplication D/OpenGLRenderer﹕ Enabling debug mode 0
12-27 12:15:03.439    1895-1926/com.example.ispotrachel.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented
12-27 12:15:03.439    1895-1926/com.example.ispotrachel.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa66b7880, error=EGL_SUCCESS
12-27 12:15:07.474    1895-1926/com.example.ispotrachel.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented
12-27 12:15:07.474    1895-1926/com.example.ispotrachel.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa66b7880, error=EGL_SUCCESS
12-27 12:15:13.993    1895-1895/com.example.ispotrachel.myapplication D/AndroidRuntime﹕    Shutting down VM 

--------- beginning of crash
12-27 12:15:13.993    1895-1895/com.example.ispotrachel.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.ispotrachel.myapplication, PID: 1895 com.firebase.client.FirebaseException: Failed to bounce to type 
        at com.firebase.client.DataSnapshot.getValue(DataSnapshot.java:196)
        at com.example.ispotrachel.myapplication.MainActivity$1.onDataChange(MainActivity.java:79) 
        at com.firebase.client.core.ValueEventRegistration$1.run(ValueEventRegistration.java:48)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

 Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.String out of START_OBJECT token
        at [Source: java.io.StringReader@c8f7297; line: 1, column: 1]
        at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:575)
        at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:46)
        at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:11)
        at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2888)
        at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2034)
        at com.firebase.client.DataSnapshot.getValue(DataSnapshot.java:192)
        at com.example.ispotrachel.myapplication.MainActivity$1.onDataChange(MainActivity.java:79)
        at com.firebase.client.core.ValueEventRegistration$1.run(ValueEventRegistration.java:48)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)device not found