title: Java equivalent of a Python functionality -> set(string)
body: <p>I want to mimic a Python functionality in Java. 
  In Python if I want unique characters in a string I can do just,</p>
  
  <pre><code>text = "i am a string"
  print set(text) # o/p is set(['a', ' ', 'g', 'i', 'm', 'n', 's', 'r', 't'])
  </code></pre>
  
  <p>How can I do this in Java trivially or directly? </p>