title: Most efficient key object type in a hash map?
body: <p>When using a <code>HashMap</code>, how much does the object type matter for element retrieval when it comes to speed? Say I use a loop to iterate through possible keys of a large hash map. What would be the most efficient key type I could use?</p>
  
  <p>As of now I am using a String for the key object type due to simplicity for my sake. While coding, this question popped up in my head and struck my curiosity. I attempted searching this question online, but couldn't quite find the answer I was looking for. Thanks!</p>