src/main/java/org/jboss/util/collection/ConcurrentSkipListMap.java
SnapshotEntry<K,V> createSnapshot() {
            V v = getValidValue();
            if (v == null)
                return null;
            return new SnapshotEntry(key, v);
        }
SnapshotEntry<K,V> createSnapshot() {
            V v = getValidValue();
            if (v == null)
                return null;
            return new SnapshotEntry(key, v);
        }
Create and return a new SnapshotEntry holding current
mapping if this node holds a valid value, else null
@return new entry or null