Cannot resolve Symbol Fehler,.... Hilfe!!!

package com.youknownow.myfirstapp;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    @override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void sendMessage(View view) {
        Intent intent = new Intent(this, DisplayMessageActivity.class);
        EditText editText = (EditText) findViewById(R.id.edit_message);
        String message = editText.getText().toString();
        intent.putExtra(EXTRA_MESSAGE, message);
        startActivity(intent);
    }

}

<?xml version="1.0" encoding="utf-8"?>
<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:orientation="horizontal">

    <EditText android:id="@+id/edit_message"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:hint="@string/edit_message"
        />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button_send"
        android:onClick="sendMessage"
         />
</LinearLayout>

protected void onNewIntent(Intent intent) {
    ......
    Bundle bundle = intent.getExtras();
    if(bundle != null){
        if(bundle.getBoolean("android.intent.extra.FROM_HOME_KEY",false) ){
            openOptionsMenu();
            restoreScreenOptions = false;
        }

        if(bundle.containsKey(KEY_HOME_PAGE) ){
            page = bundle.getInt(KEY_HOME_PAGE);
            desktop.restore();
        }
    }

    public class MeineGarage extends Object {
        private Dreirad kinderDreirad;    
        public MeineGarage() {
            kinderDreirad = new Dreirad();
        }
        public MeineGarage(Dreirad dreirad) {
            kinderDreirad = dreirad;
        }

    }
    public class Dreirad implements Fahrzeug {
       @Override
        public void bewegen() {
        }
    }
    public interface Fahrzeug {
       void bewegen();
    }
    public class Schiff implements Fahrzeug {
        @Override
        public void bewegen() {        
        }
    }

    public class Intent extends Objekt {
        private Bundle mExtras;

       // Und hier ist sogar eine Arraylist :)
        public <T extends Parcelable> ArrayList<T> getParcelableArrayListExtra(String name) {
              return mExtras == null ? null : mExtras.<T>getParcelableArrayList(name);
       }   

    }

   public class Bundel extends BaseBundle {
       
    }
    public class BaseBundle {
          ArrayMap<String, Object> mMap = null;
    }

   public class ArrayMap implements Map {
        @Override
        public void clear() {
        }
    }

    public interface Map {
       void clear(); //und andere Methoden
    }
 
    public class HashMap implements Map {
       @Override
        public void clear() {
        }
    }

    public class MeineGarage extends Object {
        private Dreirad kinderDreirad;   
        public MeineGarage() {
            kinderDreirad = new Dreirad();
        }
        public MeineGarage(Dreirad dreirad) {
            kinderDreirad = dreirad;
        }

    public class MeineGarage extends Gebaude {
        Fahrzeug fahrzeug;   
        
        public einparken(Fahrzeug obj) {
            fahrzeug = obj;
        }

        public bewegen(){
           fahrzeug.bewegen();
       }

public interface Fahrzeug{
}
public class DreiRad implements Fahrzeug {
}
public class Schiff implements Fahrzeug {
}
public class Gebaeude {

     public Fahrzeug parkPlatz;
}

// Und man parkt so:
Gebaeude garage = new Gebaeude();
garage.parkPlatz = new DreiRad();