Issue 4260 - Replace Apache Commons Lang classes

src/org/adblockplus/android/AndroidUpdateCheckDoneCallback.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 package org.adblockplus.android;
 
 import org.adblockplus.libadblockplus.UpdateCheckDoneCallback;
-import org.apache.commons.lang.StringUtils;
+import org.adblockplus.android.StringUtils;
 
 import android.content.Context;
 import android.util.Log;
 
 public class AndroidUpdateCheckDoneCallback extends UpdateCheckDoneCallback
 {
   private static final String TAG = Utils.getTag(AndroidUpdateCheckDoneCallback.class);
 
   private final Context context;
 
   public AndroidUpdateCheckDoneCallback(final Context context)
   {
     this.context = context;
   }
 
   @Override
   public void updateCheckDoneCallback(final String error)
   {
     if (StringUtils.isEmpty(error))
       return;
     Log.e(TAG, "Update check failed: " + error);
     AppUtils.showUpdateNotification(this.context, null, error);
   }
 }