title: How to create a 7 characters of alphanumeric unique id?
body: <p>I need to create alphanumeric unique IDs of length 7 or 10. Similar to the shorter version of Git commit IDs <code>(7a471b2)</code>.</p>
  
  <p>I tried UUID, but the generated unique ID is longer than I need.</p>
  
  <p>Is there a built-in method / code snippet in Java that can help here?</p>