title: Make ArrayList element case-insensitive
body: <p>In my Java application i need to compare two list's element whether it is similar or not.</p>
  
  <p>In short suppose i have two list declared like shown below</p>
  
  <pre><code>List&lt;String&gt; a = new ArrayList&lt;String&gt;();
      a.add("one");
      a.add("three");
      a.add("two");
  Collections.sort(a);
  
  
  List&lt;String&gt; a1 = new ArrayList&lt;String&gt;();
      a1.add("ONE");
      a1.add("two");
      a1.add("THREE");
  Collections.sort(a);
  </code></pre>
  
  <p>If i write a condition for equality it fails as some of list's element is in different case like</p>
  
  <pre><code>if(a.equals(a1)){
      System.out.println("equal");
  } else{
      System.out.println("not equal");
  }
  </code></pre>
  
  <p>It will display result "Not equal"</p>
  
  <p>So please tell me how i can make the list element case-insensitive in Java language only.</p>
  
  <p>Thank and regard </p>