Android customized Webview of Samsung S3 4.3 showing Fatal Error

Question

When I long press on my customized webview it shows following Error:-

java.lang.NullPointerException
at android.webkit.WebViewClassic.showSelectActionWindow(WebViewClassic.java:1974)
at android.webkit.WebViewClassic.access$8100(WebViewClassic.java:279)
at android.webkit.WebViewClassic$PrivateHandler.handleMessage(WebViewClassic.java:12888)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5419)
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:1046)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
at dalvik.system.NativeStart.main(Native Method)

I am getting error when I start action mode : public ActionMode startActionMode(ActionMode.Callback callback) {

    Log.d("dic","STARTING ACTION MODE");

    if(callback == null){  
        Log.d("longpress","callback is null");
        return null;
    }
    /*
     * Related to XC-929
     * if the new UI proposal is approved use this
     * Aug 29
     *
     **/
    if(callback.equals(mActionModeCallback)){
        Log.d("longpress","callback is equal");
        selectedText=getSelectedText();

        if(mActionMode == null){
            mActionMode = super.startActionMode(callback);
        }

        return mActionMode; 
    }

    if(isTablet){

            Log.d("longpress","callback is different");
            if(mActionMode == null){
                mActionMode = startActionMode(mActionModeCallback);


        }
            return mActionMode;
    }
    else {
        mActionMode = null;
        return null;
    }
}

and the error is :-

  STACK_TRACE=java.lang.NullPointerException
 at android.webkit.WebViewClassic.showSelectActionWindow(WebViewClassic.java:1974)
 at android.webkit.WebViewClassic.access$8100(WebViewClassic.java:279)
 at     android.webkit.WebViewClassic$PrivateHandler.handleMessage(WebViewClassic.java:12888)
   at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:176)
  at android.app.ActivityThread.main(ActivityThread.java:5419)
   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:1046)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
  at dalvik.system.NativeStart.main(Native Method)

I searched web there is nothing about webviewClassic. It showing this error only on Samsung s3 4.3 and on all other devices the same code is working fine. Please suggest me any solution clue. Thanks