Who can explain the Java operator <<=?
<p>When look into the source codes of Java HashMap,I see some codes below:</p>

<p>while (capacity &lt; initialCapacity)
     capacity &lt;&lt;= 1;</p>

<p>But I can't find the document about operator &lt;&lt;= via Google.I know operator &lt;&lt; in Java.
Any help?</p>
