new classes and interface in Collection in jdk 6

• Java 6 introduced (among others) two new interfaces: java.util.NavigableSet and java.util.NavigableMap. Here TreeSet class implements NavigableSet interface and TreeMap implements NavigableMap interface.
• PrirorityQueue is the new class added which implements Queue interface which extends Collection interface.

Here are the methods provided by these Navigable.... interfaces.

TreeSet.ceiling(e)                     Returns the lowest element >= e

TreeMap.ceilingKey(key)       Returns the lowest key >= key

TreeSet.higher(e)                     Returns the lowest element > e

TreeMap.higherKey(key)       Returns the lowest key > key

TreeSet.floor(e)                       Returns the highest element <= e

TreeMap.floorKey(key)         Returns the highest key <= key

TreeSet.lower(e)                      Returns the highest element < e

TreeMap.lowerKey(key)        Returns the highest key < key

TreeSet.pollFirst()                   Returns and removes the first entry

TreeMap.pollFirstEntry()        Returns and removes the first key-value pair

TreeSet.pollLast()                    Returns and removes the last entry

TreeMap.pollLastEntry()        Returns and removes the last key-value pair

TreeSet.descendingSet()         Returns a NavigableSet in reverse order

TreeMap.descendingMap()    Returns a NavigableMap in reverse order