title: Running first application on Android Emulator
body: <p>I am trying to run my first hello world application on the 2.3.1 emulator but I get the following error message: "The application Hello World (process com.helloworld) has stopped unexpectedly. Please try again.</p>
  
  <p>What could be the reason this is happening? </p>
  
  <p>Here is the source code: </p>
  
  <pre><code> package com.helloworld;
  
   import android.app.Activity;
   import android.os.Bundle;
   import android.view.View;
   import android.widget.Button;
  
   public class HelloWorldActivity extends Activity implements View.OnClickListener {
  
       Button button;
       int touchCount;
  
       @Override 
       public void onCreate(Bundle savedInstanceState){
           super.onCreate(savedInstanceState);
           button = new Button(this); //create the Button
           button.setText( "Touch me" ); //set its initial text
           button.setOnClickListener(this); 
           setContentView(button);    
            }
  
       public void onClick(View v) {
           touchCount++; //Increase the touchCount
           button.setText("Touched me " + touchCount + "time(s)");
       }  
      }
  </code></pre>
  
  <p>Stack Trace: </p>
  
  <pre><code>05-10 17:32:18.749: ERROR/AndroidRuntime(511): FATAL EXCEPTION: main
  05-10 17:32:18.749: ERROR/AndroidRuntime(511): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.helloworld/com.helloworld.HelloWorld.activity}: java.lang.ClassNotFoundException: com.helloworld.HelloWorld.activity in loader dalvik.system.PathClassLoader[/data/app/com.helloworld-1.apk]
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1544)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1638)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:928)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.os.Handler.dispatchMessage(Handler.java:99)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.os.Looper.loop(Looper.java:123)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.ActivityThread.main(ActivityThread.java:3647)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at java.lang.reflect.Method.invokeNative(Native Method)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at java.lang.reflect.Method.invoke(Method.java:507)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at dalvik.system.NativeStart.main(Native Method)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511): Caused by: java.lang.ClassNotFoundException: com.helloworld.HelloWorld.activity in loader dalvik.system.PathClassLoader[/data/app/com.helloworld-1.apk]
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1536)
  05-10 17:32:18.749: ERROR/AndroidRuntime(511):     ... 11 more
  </code></pre>
  
  <p><a href="http://pastebin.com/7R9pF34w" rel="nofollow">http://pastebin.com/7R9pF34w</a></p>