public void startChat(int userId)
 {
        Bundle bundle = new Bundle();
        bundle.putSerializable(OneToOneChatActivity.EXTRA_MODE,OneToOneChatActivity.Mode.SINGLE);
        bundle.putInt(OneToOneChatActivity.EXTRA_USER_ID, userId);
        OneToOneChatActivity.start(getActivity(), bundle);
 }

public static void start(Context context, Bundle bundle)  {

       Intent intent = new Intent(context, OneToOneChatActivity.class);
       intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
       intent.putExtras(bundle);
       context.startActivity(intent);
}
@Override
public void onCreate(Bundle savedInstanceState)  {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_single_chat);

}

11-29 13:26:21.258: E/AndroidRuntime(32001): FATAL EXCEPTION: main
11-29 13:26:21.258: E/AndroidRuntime(32001): Process: com.globidyne.qbchat, PID: 32001
11-29 13:26:21.258: E/AndroidRuntime(32001): java.lang.LinkageError: com.globidyne.qbchat.activities.OneToOneChatActivity
11-29 13:26:21.258: E/AndroidRuntime(32001):    at dalvik.system.DexFile.defineClassNative(Native Method)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at dalvik.system.DexFile.defineClass(DexFile.java:226)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at dalvik.system.DexPathList.findClass(DexPathList.java:321)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at com.globidyne.qbchat.fragment.FragmentOtherUser.startChat(FragmentOtherUser.java:591)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at com.globidyne.qbchat.fragment.FragmentOtherUser.onClick(FragmentOtherUser.java:367)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at android.view.View.performClick(View.java:4756)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at android.view.View$PerformClick.run(View.java:19749)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at android.os.Handler.handleCallback(Handler.java:739)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at android.os.Handler.dispatchMessage(Handler.java:95)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at android.os.Looper.loop(Looper.java:135)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at android.app.ActivityThread.main(ActivityThread.java:5221)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at java.lang.reflect.Method.invoke(Native Method)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at java.lang.reflect.Method.invoke(Method.java:372)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
11-29 13:26:21.258: E/AndroidRuntime(32001):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)