new classes and interface in Collection in jdk 6

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  • 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

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