title: comparing between two arraylists and remove extra element from there
body: <p>how do I compare two arraylists?</p>
  
  <p>I have a sdCoverList array and thumbnailList array.</p>
  
  <pre><code>02-04 11:05:05.210: I/System.out(4035): HASHED THUMBNAIL[-2122410790, 2043473787, 1914391068, 1785308349, 1656225630, 1527142911, 1398060192, 1268977473, 1139894754, 1010812035, 1242943301, 1113860582, 984777863, 855695144, 726612425, 597529706, 468446987, 339364268, 210281549]
  02-04 11:05:05.210: I/System.out(4035): SD COVER LIST[-2122410790, 2043473787, 1914391068, 1785308349, 1268977473, 1656225630, 1527142911, 1139894754, 1398060192, 1010812035, 1242943301, 1113860582, 984777863, 855695144, 726612425, 597529706, 468446987, 339364268, 210281549, 717409028]
  </code></pre>
  
  <p>In my sd cover list, i have an extra value that i want to remove away but first i'd have to compare with thumbnailList array first. if both have the same elements, don't do anything but if theres an extra, remove it from sd card.</p>
  
  <p>My array lists </p>
  
  <p>for sdCoverList:</p>
  
  <pre><code>// CHECK DIRECTORY BEFORE DELETING THEM
              File strPath = new File(Environment.getExternalStorageDirectory() + folderName+"/Covers");
              File yourDir = new File(strPath, "");
              if(yourDir.length()!=0)
              for (File f : yourDir.listFiles()) {
                  if (f.isFile())
                  {
                      String name = f.getName();
                      sdCoverList.add(name);
                      //System.out.println(sdCoverList);
                  }
  </code></pre>
  
  <p>for hashedthumbnail</p>
  
  <pre><code>for (int a=0;a&lt;=thumbnailList.size()-1;a++)
          {
              String hashed = String.valueOf(thumbnailList.get(a).hashCode());
              Log.d("hashed",hashed);
              hashedThumbnail.add(hashed);
          }
  </code></pre>