title: What are the differences between a HashMap and a Hashtable in Java?
body: <p>What are the differences between a <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/HashMap.html" rel="noreferrer"><code>HashMap</code></a> and a <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Hashtable.html" rel="noreferrer"><code>Hashtable</code></a> in Java?</p>
  
  <p>Which is more efficient for non-threaded applications?</p>