Are Spring Controllers Thread-Safe?
<p>I am writing a private utility method in a Spring Controller.  I need to use either StringBuffer or StringBuilder.  The former is thread-safe, the latter is not, but the latter is much faster.</p>

<p>Basically, it looks like this:</p>

<pre><code>private String buildTextToDisplay () {
    StringBuffer sb = new StringBuffer();
    sb.append....
    return sb.toString();
}
</code></pre>

<p>Obviously I don't want two sessions to call this simultaneously and return garbage.</p>
