Java – Collections Class

October 25, 2019 howtojava Java Util 0

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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