title: Static Factory Methods to avoid Duplicate Objects
body: <p>I was reading Joshua Bloch's "<a href="https://rads.stackoverflow.com/amzn/click/com/0201310058" rel="nofollow noreferrer" rel="nofollow noreferrer">Effective Java Programming Language Guide</a>".<br>
  He explains static factory methods could be used to avoid <strong>unnecessary duplicate objects</strong>.<br>
  I haven't quite understood this.<br>
  Could anyone explain?</p>