Java compare two map
<p>In java, I want to compare two maps, like below, do we have existing API to do this ?</p>

<p>Thanks</p>

<pre><code>Map&lt;String, String&gt; beforeMap ;
beforeMap.put("a", "1");
beforeMap.put("b", "2");
beforeMap.put("c", "3");

Map&lt;String, String&gt; afterMap ;
afterMap.put("a", "1");
afterMap.put("c", "333");

//--- it should give me:
b is missing, c value changed from '3' to '333'
</code></pre>
