Java – Collections Class

Java Collections Class methods, constructors, variables available in Java 8 release are listed below. We will publish example program on each methods ASAP.

Variables in Java Collections Class

S.No Variable & Description
1 static List EMPTY_LIST

The empty list (immutable).
2 static Map EMPTY_MAP

The empty map (immutable).
3 static Set EMPTY_SET

The empty set (immutable).

Methods in Java Collections Class

S.No Method & Description
1 static <T> boolean addAll(Collection<? super T> c, T... elements)

Adds all of the specified elements to the specified collection.
2 static <T> Queue<T> asLifoQueue(Deque<T> deque)

Returns a view of a Deque as a Last-in-first-out (Lifo) Queue.
3 static <T> int binarySearch(List<? extends Comparable<? super T>> list, T key)

Searches the specified list for the specified object using the binary search algorithm.
4 static <T> int binarySearch(List<? extends T> list, T key, Comparator<? super T> c)

Searches the specified list for the specified object using the binary search algorithm.
5 static <E> Collection<E> checkedCollection(Collection<E> c, Class<E> type)

Returns a dynamically typesafe view of the specified collection.
6 static <E> List<E> checkedList(List<E> list, Class<E> type)

Returns a dynamically typesafe view of the specified list.
7 static <K,V> Map<K,V> checkedMap(Map<K,V> m, Class<K> keyType, Class<V> valueType)

Returns a dynamically typesafe view of the specified map.
8 static <K,V> NavigableMap<K,V> checkedNavigableMap(NavigableMap<K,V> m, Class<K> keyType, Class<V> valueType)

Returns a dynamically typesafe view of the specified navigable map.
9 static <E> NavigableSet<E> checkedNavigableSet(NavigableSet<E> s, Class<E> type)

Returns a dynamically typesafe view of the specified navigable set.
10 static <E> Queue<E> checkedQueue(Queue<E> queue, Class<E> type)

Returns a dynamically typesafe view of the specified queue.
11 static <E> Set<E> checkedSet(Set<E> s, Class<E> type)

Returns a dynamically typesafe view of the specified set.
12 static <K,V> SortedMap<K,V> checkedSortedMap(SortedMap<K,V> m, Class<K> keyType, Class<V> valueType)

Returns a dynamically typesafe view of the specified sorted map.
13 static <E> SortedSet<E> checkedSortedSet(SortedSet<E> s, Class<E> type)

Returns a dynamically typesafe view of the specified sorted set.
14 static <T> void copy(List<? super T> dest, List<? extends T> src)

Copies all of the elements from one list into another.
15 static boolean disjoint(Collection<?> c1, Collection<?> c2)

Returns true if the two specified collections have no elements in common.
16 static <T> Enumeration<T> emptyEnumeration()

Returns an enumeration that has no elements.
17 static <T> Iterator<T> emptyIterator()

Returns an iterator that has no elements.
18 static <T> List<T> emptyList()

Returns an empty list (immutable).
19 static <T> ListIterator<T> emptyListIterator()

Returns a list iterator that has no elements.
20 static <K,V> Map<K,V> emptyMap()

Returns an empty map (immutable).
21 static <K,V> NavigableMap<K,V> emptyNavigableMap()

Returns an empty navigable map (immutable).
22 static <E> NavigableSet<E> emptyNavigableSet()

Returns an empty navigable set (immutable).
23 static <T> Set<T> emptySet()

Returns an empty set (immutable).
24 static <K,V> SortedMap<K,V> emptySortedMap()

Returns an empty sorted map (immutable).
25 static <E> SortedSet<E> emptySortedSet()

Returns an empty sorted set (immutable).
26 static <T> Enumeration<T> enumeration(Collection<T> c)

Returns an enumeration over the specified collection.
27 static <T> void fill(List<? super T> list, T obj)

Replaces all of the elements of the specified list with the specified element.
28 static int frequency(Collection<?> c, Object o)

Returns the number of elements in the specified collection equal to the specified object.
29 static int indexOfSubList(List<?> source, List<?> target)

Returns the starting position of the first occurrence of the specified target list within the specified source list, or -1 if there is no such occurrence.
30 static int lastIndexOfSubList(List<?> source, List<?> target)

Returns the starting position of the last occurrence of the specified target list within the specified source list, or -1 if there is no such occurrence.
31 static <T> ArrayList<T> list(Enumeration<T> e)

Returns an array list containing the elements returned by the specified enumeration in the order they are returned by the enumeration.
32 static <T extends Object & Comparable<? super T>> T max(Collection<? extends T> coll)

Returns the maximum element of the given collection, according to the natural ordering of its elements.
33 static <T> T max(Collection<? extends T> coll, Comparator<? super T> comp)

Returns the maximum element of the given collection, according to the order induced by the specified comparator.
34 static <T extends Object & Comparable<? super T>> T min(Collection<? extends T> coll)

Returns the minimum element of the given collection, according to the natural ordering of its elements.
35 static <T> T min(Collection<? extends T> coll, Comparator<? super T> comp)

Returns the minimum element of the given collection, according to the order induced by the specified comparator.
36 static <T> List<T> nCopies(int n, T o)

Returns an immutable list consisting of n copies of the specified object.
37 static <E> Set<E> newSetFromMap(Map<E,Boolean> map)

Returns a set backed by the specified map.
38 static <T> boolean replaceAll(List<T> list, T oldVal, T newVal)

Replaces all occurrences of one specified value in a list with another.
39 static void reverse(List<?> list)

Reverses the order of the elements in the specified list.
40 static <T> Comparator<T> reverseOrder()

Returns a comparator that imposes the reverse of the natural ordering on a collection of objects that implement the Comparable interface.
41 static <T> Comparator<T> reverseOrder(Comparator<T> cmp)

Returns a comparator that imposes the reverse ordering of the specified comparator.
42 static void rotate(List<?> list, int distance)

Rotates the elements in the specified list by the specified distance.
43 static void shuffle(List<?> list)

Randomly permutes the specified list using a default source of randomness.
44 static void shuffle(List<?> list, Random rnd)

Randomly permute the specified list using the specified source of randomness.
45 static <T> Set<T> singleton(T o)

Returns an immutable set containing only the specified object.
46 static <T> List<T> singletonList(T o)

Returns an immutable list containing only the specified object.
47 static <K,V> Map<K,V> singletonMap(K key, V value)

Returns an immutable map, mapping only the specified key to the specified value.
48 static <T extends Comparable<? super T>> void sort(List<T> list)

Sorts the specified list into ascending order, according to the natural ordering of its elements.
49 static <T> void sort(List<T> list, Comparator<? super T> c)

Sorts the specified list according to the order induced by the specified comparator.
50 static void swap(List<?> list, int i, int j)

Swaps the elements at the specified positions in the specified list.
51 static <T> Collection<T> synchronizedCollection(Collection<T> c)

Returns a synchronized (thread-safe) collection backed by the specified collection.
52 static <T> List<T> synchronizedList(List<T> list)

Returns a synchronized (thread-safe) list backed by the specified list.
53 static <K,V> Map<K,V> synchronizedMap(Map<K,V> m)

Returns a synchronized (thread-safe) map backed by the specified map.
54 static <K,V> NavigableMap<K,V> synchronizedNavigableMap(NavigableMap<K,V> m)

Returns a synchronized (thread-safe) navigable map backed by the specified navigable map.
55 static <T> NavigableSet<T> synchronizedNavigableSet(NavigableSet<T> s)

Returns a synchronized (thread-safe) navigable set backed by the specified navigable set.
56 static <T> Set<T> synchronizedSet(Set<T> s)

Returns a synchronized (thread-safe) set backed by the specified set.
57 static <K,V> SortedMap<K,V> synchronizedSortedMap(SortedMap<K,V> m)

Returns a synchronized (thread-safe) sorted map backed by the specified sorted map.
58 static <T> SortedSet<T> synchronizedSortedSet(SortedSet<T> s)

Returns a synchronized (thread-safe) sorted set backed by the specified sorted set.
59 static <T> Collection<T> unmodifiableCollection(Collection<? extends T> c)

Returns an unmodifiable view of the specified collection.
60 static <T> List<T> unmodifiableList(List<? extends T> list)

Returns an unmodifiable view of the specified list.
61 static <K,V> Map<K,V> unmodifiableMap(Map<? extends K,? extends V> m)

Returns an unmodifiable view of the specified map.
62 static <K,V> NavigableMap<K,V> unmodifiableNavigableMap(NavigableMap<K,? extends V> m)

Returns an unmodifiable view of the specified navigable map.
63 static <T> NavigableSet<T> unmodifiableNavigableSet(NavigableSet<T> s)

Returns an unmodifiable view of the specified navigable set.
64 static <T> Set<T> unmodifiableSet(Set<? extends T> s)

Returns an unmodifiable view of the specified set.
65 static <K,V> SortedMap<K,V> unmodifiableSortedMap(SortedMap<K,? extends V> m)

Returns an unmodifiable view of the specified sorted map.
66 static <T> SortedSet<T> unmodifiableSortedSet(SortedSet<T> s)

Returns an unmodifiable view of the specified sorted set.

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