title: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo / java.lang.ClassNotFoundException
body: <p>I'm having this error while running on my device. I've been browsing the issue and I'm pretty sure I'm not having the same issues as mentioned. Both of my activities are declared in the AndroidManifest and the intent filter is there. I have no libraries whatsoever (except v4 support library, but declaring it doesn't change the problem). I tried replacing in my Manifest <code>carpedujourproductions.quickpronote.MainActivity</code> by <code>.MainActivity</code> but still no luck. I'm running Android Studio 0.2.5 so I couldn't find how to resolve potential issues related to Java Build Path/Order and Export</p>
  
  <p>I couldn't help but noticing my MainActivity's icon in the tree had a grey cross on the upper-left corner.</p>
  
  <p>Logcat: </p>
  
  <pre><code>E/AndroidRuntime: FATAL EXCEPTION: main
          java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{carpedujourproductions.quickpronote/carpedujourproductions.quickpronote.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "carpedujourproductions.quickpronote.MainActivity" on path: DexPathList[[zip file "/data/app/carpedujourproductions.quickpronote-2.apk"],nativeLibraryDirectories=[/data/app-lib/carpedujourproductions.quickpronote-2, /vendor/lib, /system/lib]]
          at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2157)
          at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2281)
          at android.app.ActivityThread.access$600(ActivityThread.java:148)
          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1263)
          at android.os.Handler.dispatchMessage(Handler.java:99)
          at android.os.Looper.loop(Looper.java:137)
          at android.app.ActivityThread.main(ActivityThread.java:5124)
          at java.lang.reflect.Method.invokeNative(Native Method)
          at java.lang.reflect.Method.invoke(Method.java:525)
          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
          at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:110)
          at dalvik.system.NativeStart.main(Native Method)
          Caused by: java.lang.ClassNotFoundException: Didn't find class "carpedujourproductions.quickpronote.MainActivity" on path: DexPathList[[zip file "/data/app/carpedujourproductions.quickpronote-2.apk"],nativeLibraryDirectories=[/data/app-lib/carpedujourproductions.quickpronote-2, /vendor/lib, /system/lib]]
          at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
          at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
          at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
          ... 12 more
  </code></pre>
  
  <p>Feel free to browse through the code <a href="https://github.com/DaS4ilor/QuickPronote" rel="noreferrer">here</a> for AndroidManifest, MainActivity.java, FirstRun.java, etc.</p>