llection</a>&lt;<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>&gt;&nbsp;getPropertyNames()</pre>
<div class="block">Returns an immutable <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>collection</code></a> containing the property
 names available within the context of the current request/response exchange context.
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