Android Studio: ClassNotFoundException

j'ai été occupé avec mon application pendant plus d'une semaine, quand soudain:

11-12 07:59:17.860    1653-1653/nl.test.myapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{nl.test.MyApp/nl.test.MyApp.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "nl.test.myapp.MainActivity" on path: DexPathList[[zip file "/data/app/nl.test.myapp-2.apk"],nativeLibraryDirectories=[/data/app-lib/nl.test.myapp-2, /system/lib]]
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
        at android.app.ActivityThread.access0(ActivityThread.java:141)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "nl.test.myapp.MainActivity" on path: DexPathList[[zip file "/data/app/nl.test.MyApp-2.apk"],nativeLibraryDirectories=[/data/app-lib/nl.test.MyApp-2, /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:2128)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
        at android.app.ActivityThread.access0(ActivityThread.java:141)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)

voici mon AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="nl.test.myapp"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="7"
        android:targetSdkVersion="19" />

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="nl.test.myapp.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".welcomewizard.WelcomeWizardIntroPage"
            android:label="@string/app_name" />

        <activity android:name=".welcomewizard.WelcomeWizardPage1"
            android:label="@string/app_name" />

        <activity android:name=".welcomewizard.WelcomeWizardPage2"
            android:label="@string/app_name" />

        <activity android:name=".welcomewizard.WelcomeWizardPage3"
            android:label="@string/app_name" />

        <activity android:name=".welcomewizard.WelcomeWizardPage4"
            android:label="@string/app_name" />

        <activity android:name=".welcomewizard.WelcomeWizardFinishPage"
            android:label="@string/app_name" />

        <activity android:name=".CompanySelectorActivity"
            android:label="@string/compsel_actionbarlabel" />
    </application>

</manifest>

ce qui se passait après quelques problèmes avec mon R.java (l'identifiant de la vue où incorrect), après la reconstruction de la projet de ce problème dans les parages

j'ai déjà essayé L'Invalidate Cashes / restart dans le fichier IDE-menu

mise à Jour 14:51: c'est mon compilateur.fichier xml:

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="CompilerConfiguration">
    <option name="DEFAULT_COMPILER" value="Javac" />
    <resourceExtensions />
    <wildcardResourcePatterns>
      <entry name="!?*.java" />
      <entry name="!?*.form" />
      <entry name="!?*.class" />
      <entry name="!?*.groovy" />
      <entry name="!?*.scala" />
      <entry name="!?*.flex" />
      <entry name="!?*.kt" />
      <entry name="!?*.clj" />
    </wildcardResourcePatterns>
    <annotationProcessing>
      <profile default="true" name="Default" enabled="false">
        <processorPath useClasspath="true" />
      </profile>
    </annotationProcessing>
  </component>
</project>

Mon MainActivity.java file (srcmainjavanltestmyappMainActivity.java):

package nl.test.myapp;

import android.annotation.TargetApi;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.widget.RelativeLayout;

import nl.test.myapp.welcomewizard.WelcomeWizardIntroPage;

public class MainActivity extends ActionBarActivity {

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

        setBackground(R.drawable.background_grey);

        Intent intent = new Intent(this, WelcomeWizardIntroPage.class);
        startActivity(intent);
        finish();
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    private void setBackground(int drawable){
        int currentApiVersion = android.os.Build.VERSION.SDK_INT;
        if(currentApiVersion >= android.os.Build.VERSION_CODES.JELLY_BEAN){
            RelativeLayout layout = (RelativeLayout) findViewById(R.id.layout_main);
            layout.setBackground(getResources().getDrawable(drawable));
        }
    }
}