Java collection class is used exclusively with static methods that operate on or return collections. It inherits Object class.
Let's see the declaration for java.util.Collections class.
SN |
Modifier & Type |
Methods |
Descriptions |
1) |
static <T> boolean |
addAll() |
It is used to adds all of the specified elements to the specified collection. |
2) |
static <T> Queue<T> |
asLifoQueue() |
It returns a view of a Deque as a Last-in-first-out (LIFO) Queue. |
3) |
static <T> int |
binarySearch() |
It searches the list for the specified object and returns their position in a sorted list. |
4) |
static <E> Collection<E> |
checkedCollection() |
It is used to returns a dynamically typesafe view of the specified collection. |
5) |
static <E> List<E> |
checkedList() |
It is used to returns a dynamically typesafe view of the specified list. |
6) |
static <K,V> Map<K,V> |
checkedMap() |
It is used to returns a dynamically typesafe view of the specified map. |
7) |
static <K,V> NavigableMap<K,V> |
checkedNavigableMap() |
It is used to returns a dynamically typesafe view of the specified navigable map. |
8) |
static <E> NavigableSet<E> |
checkedNavigableSet() |
It is used to returns a dynamically typesafe view of the specified navigable set. |
9) |
static <E> Queue<E> |
checkedQueue() |
It is used to returns a dynamically typesafe view of the specified queue. |
10) |
static <E> Set<E> |
checkedSet() |
It is used to returns a dynamically typesafe view of the specified set. |
11) |
static <K,V> SortedMap<K,V> |
checkedSortedMap() |
It is used to returns a dynamically typesafe view of the specified sorted map. |
12) |
static <E> SortedSet<E> |
checkedSortedSet() |
It is used to returns a dynamically typesafe view of the specified sorted set. |
13) |
static <T> void |
copy() |
It is used to copy all the elements from one list into another list. |
14) |
static boolean |
disjoint() |
It returns true if the two specified collections have no elements in common. |
15) |
static <T> Enumeration<T> |
emptyEnumeration() |
It is used to get an enumeration that has no elements. |
16) |
static <T> Iterator<T> |
emptyIterator() |
It is used to get an Iterator that has no elements. |
17) |
static <T> List<T> |
emptyList() |
It is used to get a List that has no elements. |
18) |
static <T> ListIterator<T> |
emptyListIterator() |
It is used to get a List Iterator that has no elements. |
19) |
static <K,V> Map<K,V> |
emptyMap() |
It returns an empty map which is immutable. |
20) |
static <K,V> NavigableMap<K,V> |
emptyNavigableMap() |
It returns an empty navigable map which is immutable. |
21) |
static <E> NavigableSet<E> |
emptyNavigableSet() |
It is used to get an empty navigable set which is immutable in nature. |
22) |
static <T> Set<T> |
emptySet() |
It is used to get the set that has no elements. |
23) |
static <K,V> SortedMap<K,V> |
emptySortedMap() |
It returns an empty sorted map which is immutable. |
24) |
static <E> SortedSet<E> |
emptySortedSet() |
It is used to get the sorted set that has no elements. |
25) |
static <T> Enumeration<T> |
enumeration() |
It is used to get the enumeration over the specified collection. |
26) |
static <T> void |
fill() |
It is used to replace all of the elements of the specified list with the specified elements. |
27) |
static int |
frequency() |
It is used to get the number of elements in the specified collection equal to the specified object. |
28) |
static int |
indexOfSubList() |
It is used to get the starting position of the first occurrence of the specified target list within the specified source list. It returns -1 if there is no such occurrence in the specified list. |
29) |
static int |
lastIndexOfSubList() |
It is used to get the starting position of the last occurrence of the specified target list within the specified source list. It returns -1 if there is no such occurrence in the specified list. |
30) |
static <T> ArrayList<T> |
list() |
It is used to get an array list containing the elements returned by the specified enumeration in the order in which they are returned by the enumeration. |
31) |
static <T extends Object & Comparable<? super T>> T |
max() |
It is used to get the maximum value of the given collection, according to the natural ordering of its elements. |
32) |
static <T extends Object & Comparable<? super T>> T |
min() |
It is used to get the minimum value of the given collection, according to the natural ordering of its elements. |
33) |
static <T> List<T> |
nCopies() |
It is used to get an immutable list consisting of n copies of the specified object. |
34) |
static <E> Set<E> |
newSetFromMap() |
It is used to return a set backed by the specified map. |
35) |
static <T> boolean |
replaceAll() |
It is used to replace all occurrences of one specified value in a list with the other specified value. |
36) |
static void |
reverse() |
It is used to reverse the order of the elements in the specified list. |
37) |
static <T> Comparator<T> |
reverseOrder() |
It is used to get the comparator that imposes the reverse of the natural ordering on a collection of objects which implement the Comparable interface. |
38) |
static void |
rotate() |
It is used to rotate the elements in the specified list by a given distance. |
39) |
static void |
shuffle() |
It is used to randomly reorders the specified list elements using a default randomness. |
40) |
static <T> Set<T> |
singleton() |
It is used to get an immutable set which contains only the specified object. |
41) |
static <T> List<T> |
singletonList() |
It is used to get an immutable list which contains only the specified object. |
42) |
static <K,V> Map<K,V> |
singletonMap() |
It is used to get an immutable map, mapping only the specified key to the specified value. |
43) |
static <T extends Comparable<? super T>>void |
sort() |
It is used to sort the elements presents in the specified list of collection in ascending order. |
44) |
static void |
swap() |
It is used to swap the elements at the specified positions in the specified list. |
45) |
static <T> Collection<T> |
synchronizedCollection() |
It is used to get a synchronized (thread-safe) collection backed by the specified collection. |
46) |
static <T> List<T> |
synchronizedList() |
It is used to get a synchronized (thread-safe) collection backed by the specified list. |
47) |
static <K,V> Map<K,V> |
synchronizedMap() |
It is used to get a synchronized (thread-safe) map backed by the specified map. |
48) |
static <K,V> NavigableMap<K,V> |
synchronizedNavigableMap() |
It is used to get a synchronized (thread-safe) navigable map backed by the specified navigable map. |
49) |
static <T> NavigableSet<T> |
synchronizedNavigableSet() |
It is used to get a synchronized (thread-safe) navigable set backed by the specified navigable set. |
50) |
static <T> Set<T> |
synchronizedSet() |
It is used to get a synchronized (thread-safe) set backed by the specified set. |
51) |
static <K,V> SortedMap<K,V> |
synchronizedSortedMap() |
It is used to get a synchronized (thread-safe) sorted map backed by the specified sorted map. |
52) |
static <T> SortedSet<T> |
synchronizedSortedSet() |
It is used to get a synchronized (thread-safe) sorted set backed by the specified sorted set. |
53) |
static <T> Collection<T> |
unmodifiableCollection() |
It is used to get an unmodifiable view of the specified collection. |
54) |
static <T> List<T> |
unmodifiableList() |
It is used to get an unmodifiable view of the specified list. |
55) |
static <K,V> Map<K,V> |
unmodifiableMap() |
It is used to get an unmodifiable view of the specified map. |
56) |
static <K,V> NavigableMap<K,V> |
unmodifiableNavigableMap() |
It is used to get an unmodifiable view of the specified navigable map. |
57) |
static <T> NavigableSet<T> |
unmodifiableNavigableSet() |
It is used to get an unmodifiable view of the specified navigable set. |
58) |
static <T> Set<T> |
unmodifiableSet() |
It is used to get an unmodifiable view of the specified set. |
59) |
static <K,V> SortedMap<K,V> |
unmodifiableSortedMap() |
It is used to get an unmodifiable view of the specified sorted map. |
60 |
static <T> SortedSet<T> |
unmodifiableSortedSet() |
It is used to get an unmodifiable view of the specified sorted set. |
Initial collection value:[C, Core Java, Advance Java]
After adding elements collection value:[C, Core Java, Advance Java, Servlet, JSP]
After adding array collection value:[C, Core Java, Advance Java, Servlet, JSP, C#, .Net]