Android java.lang.RuntimeException: Unable to instantiate activity ComponentInfo

Question

Ok guys this doesn't make sense to me at all and I don't understand why I am getting this error in my app. I have registered the activity class in the android manifrest xml..

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.mobile.batteryhelper/com.mobile.batteryhelper.Battery}:
java.lang.ClassNotFoundException: Caused by: java.lang.ClassNotFoundException: com.mobile.batteryhelper.Battery in loader dalvik.system.PathClassLoader[/mnt/asec/com.mobile.batteryhelper-1/pkg.apk]

Here is the androidmanifest.xml. Yes the .Battery class extends Activity also.

<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".Battery"
              android:label="@string/app_name"
               android:screenOrientation="portrait">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

Answer 1

Have you tried to clean your workspace. Goto Project->Clean and select your project. For some reason eclipse doesn't build my manifest automatically.

Answer 2

You have put 3rd party library in library folder and reference them. Go to Properties/ Java Build Path/ Libraries/ Add External JARs.

Check the Jar files in the Properties/ Java Build Path/ Order and Export

Answer 3

Have you tried to initialise anything in your class before OnCreate gets called?
If you initialise static variables (for example) it can give you this (infuriatingly obtuse) error.