title: ClassNotFoundException: Didn't find class "com.example.app.MainActivity" for every app I create
body: <p>Hello<br>I keep getting a ClassNotFoundException every time I create an Android application in eclipse. This is something that has never happened before up until this morning after using eclipse for months. It might also be worth mentioning that I installed google play services through the SDK manager this morning<br><br>Logcat:<br> </p>
  
  <pre><code>11-03 12:39:29.080: E/AndroidRuntime(27547): FATAL EXCEPTION: main
  11-03 12:39:29.080: E/AndroidRuntime(27547): Process: com.example.app, PID: 27547
  11-03 12:39:29.080: E/AndroidRuntime(27547): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.app/com.example.app.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.app.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.app-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.app-1, /vendor/lib, /system/lib]]
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2231)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.access$900(ActivityThread.java:161)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.os.Handler.dispatchMessage(Handler.java:102)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.os.Looper.loop(Looper.java:157)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.main(ActivityThread.java:5356)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.reflect.Method.invokeNative(Native Method)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.reflect.Method.invoke(Method.java:515)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at dalvik.system.NativeStart.main(Native Method)
  11-03 12:39:29.080: E/AndroidRuntime(27547): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.app.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.app-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.app-1, /vendor/lib, /system/lib]]
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:67)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.Instrumentation.newActivity(Instrumentation.java:1079)
  11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2222)
  </code></pre>
  
  <p><br><br>
  Manifest.xml:<br></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.example.app"
      android:versionCode="1"
      android:versionName="1.0" &gt;
  
      &lt;uses-sdk
          android:minSdkVersion="8"
          android:targetSdkVersion="19" /&gt;
  
      &lt;application
          android:allowBackup="true"
          android:icon="@drawable/ic_launcher"
          android:label="@string/app_name"
          android:theme="@style/AppTheme" &gt;
          &lt;activity
              android:name=".MainActivity"
              android:label="@string/app_name" &gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
  
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
      &lt;/application&gt;
  
  &lt;/manifest&gt;
  </code></pre>
  
  <p><br><br>Any help with this would be really appreciated as I am at a loss with it.</p>
  
  <p><br><br> eclipse:<br>
  <img src="https://i.stack.imgur.com/WhUGb.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/MB8jo.png" alt="enter image description here">
    <br><br></p>