The entire collection must be in memory for use, and the entire collection must be serialized to record the smallest change. XL2 collections do not require all elements to be in memory for access and mutation. XL2 collections can be very large and at the same time require very little memory. The sorted set and sorted map implementations represent size with a long for the adventurous. XL2SortedSet and XL2SortedMap are implemented with a skip list.
Skip lists approach balanced tree performance without requiring rebalancing.
This skip list automatically manages leveling and probability. Learn more about skip lists from the source, William Pugh's home page . Iterators and sub-collections are persistent. All iterators implement xl2.odb.collections.FailFast so fail-fast behavior can be disabled. Sun, Sun Microsystems, the Sun Logo and Java are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries.