Java ConcurrentSkipListSet.ceiling() is a method in the Java ConcurrentSkipListSet class that retrieves the smallest element greater than or equal to a given element, or null if no such element exists. It is thread-safe and used in ordered, concurrent environments. Introduced in Java 2004 with Java 5, ceiling() is commonly utilized in range queries and sorted set operations.

https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentSkipListSet.html