<p> The method seems to be building a String using concatenation in a loop.
In each iteration, the String is converted to a StringBuffer/StringBuilder,
   appended to, and converted back to a String.
   This can lead to a cost quadratic in the number of iterations,
   as the growing string is recopied in each iteration. </p>

<p>Better performance can be obtained by using
a StringBuffer (or StringBuilder in Java 1.5) explicitly.</p>

<p> For example:</p>
<pre>
  // This is bad
  String s = "";
  for (int i = 0; i &lt; field.length; ++i) {
    s = s + field[i];
  }

  // This is better
  StringBuffer buf = new StringBuffer();
  for (int i = 0; i &lt; field.length; ++i) {
    buf.append(field[i]);
  }
  String s = buf.toString();
</pre>

<p>
  This rule is deprecated, use {rule:squid:S1643} instead.
</p>