private void checkCollectionType(final Class collectionType) {
            if (!FROM_STRING.containsKey(collectionType) || !TO_STRING.containsKey(collectionType) || !TO_DISPLAY_STRING.containsKey(collectionType)) {
                throw new IllegalArgumentException("Cannot create a SystemProperty containing a collection of type " + collectionType.getName());
            }
            if (Collections.class.isAssignableFrom(collectionType)) {
                throw new IllegalArgumentException("A collection cannot contain a collection");
            }
        }
Validates the details of the SystemProperty, and generates one if it's valid.

@return A SystemProperty object
@throws IllegalArgumentException if incorrect arguments have been supplied to the builder
xmppserver/src/main/java/org/jivesoftware/util/SystemProperty.java