getClass().getResourceAsStream("/folder") return null
<p>I have tried to list jar folder files using </p>

<p><code>getClass().getResourceAsStream("/folderName")</code> it return <code>null</code></p>

<p>but <code>getClass().getResourceAsStream("folderName/fileName")</code> not <code>null</code> </p>

<p><strong>what is the difference?</strong> </p>

<p>it works in eclipse but not in <code>jar</code> file</p>