src/main/java/org/jivesoftware/smack/util/collections/AbstractReferenceMap.java
protected HashEntry<K, V> getEntry(Object key) {
        if (key == null) {
            return null;
        } else {
            return super.getEntry(key);
        }
    }
protected HashEntry<K, V> getEntry(Object key) {
        if (key == null) {
            return null;
        } else {
            return super.getEntry(key);
        }
    }
Gets the entry mapped to the key specified.

@param key
the key
@return the entry, null if no match