Map</code>. Otherwise, returns <code>null</code>.

 <p>
 The <code>Iterator</code> returned must contain zero or more instances of <a href="https://docs.oracle.com/javase/7/docs/api/java/beans/FeatureDescriptor.html?is-external=true" title="class or interface in java.beans"><code>FeatureDescriptor</code></a>. Each
 info object contains information about a key in the Map, and is initialized as follows:
 <ul>
 <li>displayName - The return value of calling the <code>toString</code> method on this key, or <code