Issue 4231 - Fix unstable FilterEngineTest.testSetRemoveFilterChangeCallback

libadblockplus-android/src/org/adblockplus/libadblockplus/FileSystemUtils.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
@@ skipping 16 matching lines @@
 
 public class FileSystemUtils
 {
   /**
    * Read all the file data to string
    *
    * @param file path to read data
    * @return file data
    * @throws java.io.FileNotFoundException
    */
-  public String readFile(File file) throws FileNotFoundException
+  public static String readFile(File file) throws FileNotFoundException
   {
     Scanner scanner = null;
     try
     {
       scanner = new Scanner(file);
       return scanner.useDelimiter("\\A").next();
     }
     catch (NoSuchElementException e)
     {
       return "";
     }
     finally
     {
       if (scanner != null)
       {
         scanner.close();
       }
     }
   }
 
   /**
    * Write data to file (with rewriting)
    *
    * @param file file
    * @param data file data
    */
-  public void writeFile(File file, String data) throws IOException
+  public static void writeFile(File file, String data) throws IOException
   {
     FileOutputStream fos = null;
     try
     {
       fos = new FileOutputStream(file);
       if (data != null)
       {
         fos.write(data.getBytes());
       }
     }
     finally
     {
       if (fos != null)
       {
         try
         {
           fos.close();

[diegocarloslima, 2017/04/27 12:22:40]

Are we using Java 7 already in libadblockplus-android? This could be done with a
try-with-resources statement

[anton, 2017/04/28 08:25:45]

it's not clear but seems that "not yet". For now i don't use Java 7 features
without special need for it.

         }
         catch (IOException e)
         {
           // ignored
         }
       }
     }
   }
 
   /**
    * Generate unique filename
    *
    * @param prefix prefix
    * @param suffix suffix
    * @return generated unique filename
    */
-  public String generateUniqueFileName(String prefix, String suffix)
+  public static String generateUniqueFileName(String prefix, String suffix)
   {
     StringBuilder sb = new StringBuilder();
     if (prefix != null)
     {
       sb.append(prefix);
     }
 
     sb.append(UUID.randomUUID().toString());
 
     if (suffix != null)
     {
       sb.append(suffix);
     }
 
     return sb.toString();
   }
 }