title: Difference between map.keySet().contains() and map.containsKey()
body: <p>Is there any difference between these two statements when I just want to set an 'if' statement?</p>
  
  <pre><code>// it is a HashMap
  
  if (map.keySet().contains(myKey)) { //do something...}
  
  if (map.containsKey(myKey)){ //do the same thing...}
  </code></pre>