title: Difference between String, String Builders, Character Arrays and Arraylist
body: <p>Strings are immutable. Stringbuilders are not, so you can append characters at the end. Strings are character arrays if i am not wrong, than why do we use character arrays separately and Strings separately, Do we really need to use character arrays?</p>
  
  <p>Secondly, there are character arrays and then there are Arraylists. Array lists holds complete objects? I am a bit confused actually.</p>
  
  <pre><code>String cat = "c" + "a" + "t";
  cat = cat + cat;
  
  StringBuilder sb = new StringBuilder();
  sb.append(city);
  sb.append(", ");
  sb.append(state);
  sb.toString();
  
  Char apple[5]={'a','p','p','l','e'};
  
  Arraylist&lt;MyCar&gt;obj = new Arraylist&lt;MyCar&gt;();
  </code></pre>
  
  <p>Which should be used where?</p>