A ConcurrentNavigableMap method toString() converts a string representation of this map. The string representation consists of a list of key-value mappings in the order returned by the map's entrySet view's iterator, enclosed in braces ("{}"). It returns a string representation of this map.

A ConcurrentNavigableMap method floorKey() retrieves the greatest key less than or equal to the given key. It returns the greatest key less than or equal to the given key, or null if there is no such key.

A ConcurrentNavigableMap method computeIfAbsent() computes If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map unless null. The function is NOT guaranteed to be applied once atomically only if the value is not present.

A ConcurrentNavigableMap method clone() creates a shallow copy of this ConcurrentSkipListMap instance. (The keys and values themselves are not cloned). It returns a shallow copy of this map.

A ConcurrentSkipListMap method tailMap() creates a view of the portion of this map whose keys are greater than or equal to fromKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. It returns a view of the portion of this map whose keys are greater than or equal to fromKey.

A ConcurrentSkipListMap method equals() compares the specified object with this map for equality. It returns boolean value true, if the given object is also a map and the two maps represent the same mappings, otherwise false.

A ConcurrentSkipListMap method size() determines number of entries present in this map. It returns the number of key-value mappings in this map.

A ConcurrentSkipListMap method putAll() copies all of the mappings from the specified map to this map. The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map.

A ConcurrentSkipListMap method put() associates the specified value with the specified key in this map (optional operation). If the map previously contained a mapping for the key, the old value is replaced by the specified value. It returns the previous value associated with key, or null if there was no mapping for key.

A ConcurrentSkipListMap method isEmpty() determines whether a map contains no key-value mappings. It returns boolean value true, if this map contains no key-value mappings, otherwise false.