GUACAMOLE-635: Heap pollution is not possible within SimpleDirectory(ObjectType... objects).

From https://docs.oracle.com/javase/tutorial/java/generics/nonReifiableVarargsType.html#vulnerabilities:

"Heap pollution occurs when a variable of a parameterized type refers
to an object that is not of that parameterized type."

In this case, the parameterized type (ObjectType) and the array of that
type within this constructor are always used as their formal types.

guacamole-ext/src/main/java/org/apache/guacamole/net/auth/simple/SimpleDirectory.java

@@ -85,6 +85,7 @@ public class SimpleDirectory<ObjectType extends Identifiable>
      * @param objects
      *     The objects that should be present in this directory.
      */
+    @SafeVarargs
     public SimpleDirectory(ObjectType... objects) {
         this(Arrays.asList(objects));
     }