title: Java- for loop using << operator
body: <p>I'm stuying this code and I don't understand what this line does: <code>[(y &lt;&lt; 3) + x]</code></p>
  
  <pre><code>    for (int y = 0; y &lt;= 7; ++y) {
              for (int x = 0; x &lt;= 7; ++x) {
                  final String pieceCode = pieceCodes[(y &lt;&lt; 3) + x];
                  if (pieceCode.length() != 2) throw new IllegalArgumentException();
                  if (!pieceCode.equals("--")) {
                      pieces[((7 - y) &lt;&lt; 3) + x] = CheckersPiece.valueOf(pieceCode.charAt(0), pieceCode.charAt(1));   
                  }
              }
          }
  </code></pre>