diff --git a/app/src/main/java/com/jayway/ormlite/DatabaseHelper.java b/app/src/main/java/com/jayway/ormlite/DatabaseHelper.java
index f5a935f..2725ac6 100644
--- a/app/src/main/java/com/jayway/ormlite/DatabaseHelper.java
+++ b/app/src/main/java/com/jayway/ormlite/DatabaseHelper.java
@@ -30,6 +30,7 @@ public class DatabaseHelper extends OrmLiteSqliteOpenHelper {
 
     public DatabaseHelper(Context context) {
         super(context, DATABASE_NAME, null, DATABASE_VERSION);
+        sDatabaseHelper = this;
     }
 
     @Override
@@ -134,4 +135,4 @@ public void close() {
     public static DatabaseHelper getInstance() {
         return sDatabaseHelper;
     }
-}
\ No newline at end of file
+}
diff --git a/app/src/main/java/com/jayway/ormlite/MainActivity.java b/app/src/main/java/com/jayway/ormlite/MainActivity.java
index f53d5ba..6a967c9 100644
--- a/app/src/main/java/com/jayway/ormlite/MainActivity.java
+++ b/app/src/main/java/com/jayway/ormlite/MainActivity.java
@@ -20,7 +20,7 @@ public class MainActivity extends AppCompatActivity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        setContentView(R.layout.activity_main);
+        setContentView(R.layout.activity_main);     
     }
 
     private void example() throws SQLException {
@@ -50,14 +50,14 @@ private void example() throws SQLException {
         userDao.create(user);
 
         // Obtain the role
-        user = userDao.queryForId(0);
+        user = userDao.queryForId(user.getId());
         Role role = user.getRole();
 
         // One-to-many
         user = new User().setName("Clause");
         userDao.create(user); // Without creating the object this won't work.
 
-        final Dao<Email, Integer> emailsDao = DatabaseHelper.getInstance().getEmailDao();
+        final Dao<Email, Integer> emailsDao = helper.getEmailDao();
         emailsDao.create(new Email(user).setEmail("my@example.com"));
         emailsDao.create(new Email(user).setEmail("my2@example.com"));
 
diff --git a/app/src/main/java/com/jayway/ormlite/model/Role.java b/app/src/main/java/com/jayway/ormlite/model/Role.java
index 552133b..a3c386e 100644
--- a/app/src/main/java/com/jayway/ormlite/model/Role.java
+++ b/app/src/main/java/com/jayway/ormlite/model/Role.java
@@ -6,6 +6,10 @@
 @DatabaseTable(tableName = Role.TABLE_NAME_ROLES)
 public class Role {
 
+    public Role() {
+        // Don't forget the empty constructor, needed by ORMLite.
+    }  
+    
     public static final String TABLE_NAME_ROLES = "roles";
 
     public static final String FIELD_NAME_ID   = "id";
diff --git a/app/src/main/java/com/jayway/ormlite/model/User.java b/app/src/main/java/com/jayway/ormlite/model/User.java
index 56418b5..4438302 100644
--- a/app/src/main/java/com/jayway/ormlite/model/User.java
+++ b/app/src/main/java/com/jayway/ormlite/model/User.java
@@ -9,6 +9,10 @@
 @DatabaseTable(tableName = User.TABLE_NAME_USERS, daoClass = CustomDao.class)
 public class User {
 
+    public User() {
+        // Don't forget the empty constructor, needed by ORMLite.
+    }   
+    
     public static final String TABLE_NAME_USERS = "users";
 
     public static final String FIELD_NAME_ID     = "id";