LinkedList (Java SE 9 & JDK 9 ) (original) (raw)

Field Summary

 * ### Fields inherited from class java.util.[AbstractList](../../java/util/AbstractList.html "class in java.util")  
 `[modCount](../../java/util/AbstractList.html#modCount)`

Constructor Summary

Constructors

Constructor	Description
LinkedList()	Constructs an empty list.
LinkedList(Collection<? extends E> c)	Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Method Summary

All Methods Instance Methods Concrete Methods

Modifier and Type	Method	Description
void	add(int index,E element)	Inserts the specified element at the specified position in this list.
boolean	add(E e)	Appends the specified element to the end of this list.
boolean	addAll(int index,Collection<? extends E> c)	Inserts all of the elements in the specified collection into this list, starting at the specified position.
boolean	addAll(Collection<? extends E> c)	Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator.
void	addFirst(E e)	Inserts the specified element at the beginning of this list.
void	addLast(E e)	Appends the specified element to the end of this list.
void	clear()	Removes all of the elements from this list.
Object	clone()	Returns a shallow copy of this LinkedList.
boolean	contains(Object o)	Returns true if this list contains the specified element.
Iterator<E>	descendingIterator()	Returns an iterator over the elements in this deque in reverse sequential order.
E	element()	Retrieves, but does not remove, the head (first element) of this list.
E	get(int index)	Returns the element at the specified position in this list.
E	getFirst()	Returns the first element in this list.
E	getLast()	Returns the last element in this list.
int	indexOf(Object o)	Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
int	lastIndexOf(Object o)	Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
ListIterator<E>	listIterator(int index)	Returns a list-iterator of the elements in this list (in proper sequence), starting at the specified position in the list.
boolean	offer(E e)	Adds the specified element as the tail (last element) of this list.
boolean	offerFirst(E e)	Inserts the specified element at the front of this list.
boolean	offerLast(E e)	Inserts the specified element at the end of this list.
E	peek()	Retrieves, but does not remove, the head (first element) of this list.
E	peekFirst()	Retrieves, but does not remove, the first element of this list, or returns null if this list is empty.
E	peekLast()	Retrieves, but does not remove, the last element of this list, or returns null if this list is empty.
E	poll()	Retrieves and removes the head (first element) of this list.
E	pollFirst()	Retrieves and removes the first element of this list, or returns null if this list is empty.
E	pollLast()	Retrieves and removes the last element of this list, or returns null if this list is empty.
E	pop()	Pops an element from the stack represented by this list.
void	push(E e)	Pushes an element onto the stack represented by this list.
E	remove()	Retrieves and removes the head (first element) of this list.
E	remove(int index)	Removes the element at the specified position in this list.
boolean	remove(Object o)	Removes the first occurrence of the specified element from this list, if it is present.
E	removeFirst()	Removes and returns the first element from this list.
boolean	removeFirstOccurrence(Object o)	Removes the first occurrence of the specified element in this list (when traversing the list from head to tail).
E	removeLast()	Removes and returns the last element from this list.
boolean	removeLastOccurrence(Object o)	Removes the last occurrence of the specified element in this list (when traversing the list from head to tail).
E	set(int index,E element)	Replaces the element at the specified position in this list with the specified element.
int	size()	Returns the number of elements in this list.
Spliterator<E>	spliterator()	Creates a late-binding and fail-fast Spliterator over the elements in this list.
Object[]	toArray()	Returns an array containing all of the elements in this list in proper sequence (from first to last element).
T[]	toArray(T[] a)	Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.

   * ### Methods inherited from class java.util.[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")  
   `[containsAll](../../java/util/AbstractCollection.html#containsAll-java.util.Collection-), [isEmpty](../../java/util/AbstractCollection.html#isEmpty--), [removeAll](../../java/util/AbstractCollection.html#removeAll-java.util.Collection-), [retainAll](../../java/util/AbstractCollection.html#retainAll-java.util.Collection-), [toString](../../java/util/AbstractCollection.html#toString--)`  
   * ### Methods inherited from class java.util.[AbstractList](../../java/util/AbstractList.html "class in java.util")  
   `[equals](../../java/util/AbstractList.html#equals-java.lang.Object-), [hashCode](../../java/util/AbstractList.html#hashCode--), [listIterator](../../java/util/AbstractList.html#listIterator--), [removeRange](../../java/util/AbstractList.html#removeRange-int-int-), [subList](../../java/util/AbstractList.html#subList-int-int-)`  
   * ### Methods inherited from class java.util.[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")  
   `[iterator](../../java/util/AbstractSequentialList.html#iterator--)`  
   * ### Methods inherited from interface java.util.[Collection](../../java/util/Collection.html "interface in java.util")  
   `[parallelStream](../../java/util/Collection.html#parallelStream--), [removeIf](../../java/util/Collection.html#removeIf-java.util.function.Predicate-), [stream](../../java/util/Collection.html#stream--)`  
   * ### Methods inherited from interface java.util.[Deque](../../java/util/Deque.html "interface in java.util")  
   `[iterator](../../java/util/Deque.html#iterator--)`  
   * ### Methods inherited from interface java.lang.[Iterable](../../java/lang/Iterable.html "interface in java.lang")  
   `[forEach](../../java/lang/Iterable.html#forEach-java.util.function.Consumer-)`  
   * ### Methods inherited from interface java.util.[List](../../java/util/List.html "interface in java.util")  
   `[containsAll](../../java/util/List.html#containsAll-java.util.Collection-), [equals](../../java/util/List.html#equals-java.lang.Object-), [hashCode](../../java/util/List.html#hashCode--), [isEmpty](../../java/util/List.html#isEmpty--), [iterator](../../java/util/List.html#iterator--), [listIterator](../../java/util/List.html#listIterator--), [of](../../java/util/List.html#of--), [of](../../java/util/List.html#of-E-), [of](../../java/util/List.html#of-E...-), [of](../../java/util/List.html#of-E-E-), [of](../../java/util/List.html#of-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-E-E-), [of](../../java/util/List.html#of-E-E-E-E-E-E-E-E-E-E-), [removeAll](../../java/util/List.html#removeAll-java.util.Collection-), [replaceAll](../../java/util/List.html#replaceAll-java.util.function.UnaryOperator-), [retainAll](../../java/util/List.html#retainAll-java.util.Collection-), [sort](../../java/util/List.html#sort-java.util.Comparator-), [subList](../../java/util/List.html#subList-int-int-)`  
   * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang")  
   `[finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`

Constructor Detail

 * #### LinkedList  
 public LinkedList()  
 Constructs an empty list.  
 * #### LinkedList  
 public LinkedList([Collection](../../java/util/Collection.html "interface in java.util")<? extends [E](../../java/util/LinkedList.html "type parameter in LinkedList")> c)  
 Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.  
 Parameters:  
 `c` \- the collection whose elements are to be placed into this list  
 Throws:  
 `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null

Method Detail

* #### getFirst  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") getFirst()  
Returns the first element in this list.  
Specified by:  
`[getFirst](../../java/util/Deque.html#getFirst--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the first element in this list  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
* #### getLast  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") getLast()  
Returns the last element in this list.  
Specified by:  
`[getLast](../../java/util/Deque.html#getLast--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the last element in this list  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
* #### removeFirst  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") removeFirst()  
Removes and returns the first element from this list.  
Specified by:  
`[removeFirst](../../java/util/Deque.html#removeFirst--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the first element from this list  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
* #### removeLast  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") removeLast()  
Removes and returns the last element from this list.  
Specified by:  
`[removeLast](../../java/util/Deque.html#removeLast--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the last element from this list  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
* #### addFirst  
public void addFirst([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Inserts the specified element at the beginning of this list.  
Specified by:  
`[addFirst](../../java/util/Deque.html#addFirst-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- the element to add  
* #### addLast  
public void addLast([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Appends the specified element to the end of this list.  
This method is equivalent to [add(E)](../../java/util/LinkedList.html#add-E-).  
Specified by:  
`[addLast](../../java/util/Deque.html#addLast-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- the element to add  
* #### contains  
public boolean contains([Object](../../java/lang/Object.html "class in java.lang") o)  
Returns `true` if this list contains the specified element. More formally, returns `true` if and only if this list contains at least one element `e` such that`Objects.equals(o, e)`.  
Specified by:  
`[contains](../../java/util/Collection.html#contains-java.lang.Object-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[contains](../../java/util/Deque.html#contains-java.lang.Object-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[contains](../../java/util/List.html#contains-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[contains](../../java/util/AbstractCollection.html#contains-java.lang.Object-)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`o` \- element whose presence in this list is to be tested  
Returns:  
`true` if this list contains the specified element  
* #### size  
public int size()  
Returns the number of elements in this list.  
Specified by:  
`[size](../../java/util/Collection.html#size--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[size](../../java/util/Deque.html#size--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[size](../../java/util/List.html#size--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[size](../../java/util/AbstractCollection.html#size--)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the number of elements in this list  
* #### add  
public boolean add([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Appends the specified element to the end of this list.  
This method is equivalent to [addLast(E)](../../java/util/LinkedList.html#addLast-E-).  
Specified by:  
`[add](../../java/util/Collection.html#add-E-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[add](../../java/util/Deque.html#add-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[add](../../java/util/List.html#add-E-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[add](../../java/util/Queue.html#add-E-)` in interface `[Queue](../../java/util/Queue.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[add](../../java/util/AbstractList.html#add-E-)` in class `[AbstractList](../../java/util/AbstractList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- element to be appended to this list  
Returns:  
`true` (as specified by [Collection.add(E)](../../java/util/Collection.html#add-E-))  
* #### remove  
public boolean remove([Object](../../java/lang/Object.html "class in java.lang") o)  
Removes the first occurrence of the specified element from this list, if it is present. If this list does not contain the element, it is unchanged. More formally, removes the element with the lowest index`i` such that`Objects.equals(o, get(i))` (if such an element exists). Returns `true` if this list contained the specified element (or equivalently, if this list changed as a result of the call).  
Specified by:  
`[remove](../../java/util/Collection.html#remove-java.lang.Object-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[remove](../../java/util/Deque.html#remove-java.lang.Object-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[remove](../../java/util/List.html#remove-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[remove](../../java/util/AbstractCollection.html#remove-java.lang.Object-)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`o` \- element to be removed from this list, if present  
Returns:  
`true` if this list contained the specified element  
* #### addAll  
public boolean addAll([Collection](../../java/util/Collection.html "interface in java.util")<? extends [E](../../java/util/LinkedList.html "type parameter in LinkedList")> c)  
Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)  
Specified by:  
`[addAll](../../java/util/Collection.html#addAll-java.util.Collection-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[addAll](../../java/util/Deque.html#addAll-java.util.Collection-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[addAll](../../java/util/List.html#addAll-java.util.Collection-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[addAll](../../java/util/AbstractCollection.html#addAll-java.util.Collection-)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`c` \- collection containing elements to be added to this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
See Also:  
[AbstractCollection.add(Object)](../../java/util/AbstractCollection.html#add-E-)  
* #### addAll  
public boolean addAll(int index,  
                      [Collection](../../java/util/Collection.html "interface in java.util")<? extends [E](../../java/util/LinkedList.html "type parameter in LinkedList")> c)  
Inserts all of the elements in the specified collection into this list, starting at the specified position. Shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices). The new elements will appear in the list in the order that they are returned by the specified collection's iterator.  
Specified by:  
`[addAll](../../java/util/List.html#addAll-int-java.util.Collection-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[addAll](../../java/util/AbstractSequentialList.html#addAll-int-java.util.Collection-)` in class `[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`index` \- index at which to insert the first element from the specified collection  
`c` \- collection containing elements to be added to this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
* #### clear  
public void clear()  
Removes all of the elements from this list. The list will be empty after this call returns.  
Specified by:  
`[clear](../../java/util/Collection.html#clear--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[clear](../../java/util/List.html#clear--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[clear](../../java/util/AbstractList.html#clear--)` in class `[AbstractList](../../java/util/AbstractList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
* #### get  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") get(int index)  
Returns the element at the specified position in this list.  
Specified by:  
`[get](../../java/util/List.html#get-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[get](../../java/util/AbstractSequentialList.html#get-int-)` in class `[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`index` \- index of the element to return  
Returns:  
the element at the specified position in this list  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### set  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") set(int index,  
             [E](../../java/util/LinkedList.html "type parameter in LinkedList") element)  
Replaces the element at the specified position in this list with the specified element.  
Specified by:  
`[set](../../java/util/List.html#set-int-E-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[set](../../java/util/AbstractSequentialList.html#set-int-E-)` in class `[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`index` \- index of the element to replace  
`element` \- element to be stored at the specified position  
Returns:  
the element previously at the specified position  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### add  
public void add(int index,  
                [E](../../java/util/LinkedList.html "type parameter in LinkedList") element)  
Inserts the specified element at the specified position in this list. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).  
Specified by:  
`[add](../../java/util/List.html#add-int-E-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[add](../../java/util/AbstractSequentialList.html#add-int-E-)` in class `[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`index` \- index at which the specified element is to be inserted  
`element` \- element to be inserted  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
* #### remove  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") remove(int index)  
Removes the element at the specified position in this list. Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.  
Specified by:  
`[remove](../../java/util/List.html#remove-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[remove](../../java/util/AbstractSequentialList.html#remove-int-)` in class `[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`index` \- the index of the element to be removed  
Returns:  
the element previously at the specified position  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### indexOf  
public int indexOf([Object](../../java/lang/Object.html "class in java.lang") o)  
Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the lowest index `i` such that`Objects.equals(o, get(i))`, or -1 if there is no such index.  
Specified by:  
`[indexOf](../../java/util/List.html#indexOf-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[indexOf](../../java/util/AbstractList.html#indexOf-java.lang.Object-)` in class `[AbstractList](../../java/util/AbstractList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`o` \- element to search for  
Returns:  
the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element  
* #### lastIndexOf  
public int lastIndexOf([Object](../../java/lang/Object.html "class in java.lang") o)  
Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the highest index `i` such that`Objects.equals(o, get(i))`, or -1 if there is no such index.  
Specified by:  
`[lastIndexOf](../../java/util/List.html#lastIndexOf-java.lang.Object-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[lastIndexOf](../../java/util/AbstractList.html#lastIndexOf-java.lang.Object-)` in class `[AbstractList](../../java/util/AbstractList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`o` \- element to search for  
Returns:  
the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element  
* #### peek  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") peek()  
Retrieves, but does not remove, the head (first element) of this list.  
Specified by:  
`[peek](../../java/util/Deque.html#peek--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[peek](../../java/util/Queue.html#peek--)` in interface `[Queue](../../java/util/Queue.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the head of this list, or `null` if this list is empty  
Since:  
1.5  
* #### element  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") element()  
Retrieves, but does not remove, the head (first element) of this list.  
Specified by:  
`[element](../../java/util/Deque.html#element--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[element](../../java/util/Queue.html#element--)` in interface `[Queue](../../java/util/Queue.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the head of this list  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
Since:  
1.5  
* #### poll  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") poll()  
Retrieves and removes the head (first element) of this list.  
Specified by:  
`[poll](../../java/util/Deque.html#poll--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[poll](../../java/util/Queue.html#poll--)` in interface `[Queue](../../java/util/Queue.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the head of this list, or `null` if this list is empty  
Since:  
1.5  
* #### remove  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") remove()  
Retrieves and removes the head (first element) of this list.  
Specified by:  
`[remove](../../java/util/Deque.html#remove--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[remove](../../java/util/Queue.html#remove--)` in interface `[Queue](../../java/util/Queue.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the head of this list  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
Since:  
1.5  
* #### offer  
public boolean offer([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Adds the specified element as the tail (last element) of this list.  
Specified by:  
`[offer](../../java/util/Deque.html#offer-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[offer](../../java/util/Queue.html#offer-E-)` in interface `[Queue](../../java/util/Queue.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- the element to add  
Returns:  
`true` (as specified by [Queue.offer(E)](../../java/util/Queue.html#offer-E-))  
Since:  
1.5  
* #### offerFirst  
public boolean offerFirst([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Inserts the specified element at the front of this list.  
Specified by:  
`[offerFirst](../../java/util/Deque.html#offerFirst-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- the element to insert  
Returns:  
`true` (as specified by [Deque.offerFirst(E)](../../java/util/Deque.html#offerFirst-E-))  
Since:  
1.6  
* #### offerLast  
public boolean offerLast([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Inserts the specified element at the end of this list.  
Specified by:  
`[offerLast](../../java/util/Deque.html#offerLast-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- the element to insert  
Returns:  
`true` (as specified by [Deque.offerLast(E)](../../java/util/Deque.html#offerLast-E-))  
Since:  
1.6  
* #### peekFirst  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") peekFirst()  
Retrieves, but does not remove, the first element of this list, or returns `null` if this list is empty.  
Specified by:  
`[peekFirst](../../java/util/Deque.html#peekFirst--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the first element of this list, or `null` if this list is empty  
Since:  
1.6  
* #### peekLast  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") peekLast()  
Retrieves, but does not remove, the last element of this list, or returns `null` if this list is empty.  
Specified by:  
`[peekLast](../../java/util/Deque.html#peekLast--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the last element of this list, or `null` if this list is empty  
Since:  
1.6  
* #### pollFirst  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") pollFirst()  
Retrieves and removes the first element of this list, or returns `null` if this list is empty.  
Specified by:  
`[pollFirst](../../java/util/Deque.html#pollFirst--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the first element of this list, or `null` if this list is empty  
Since:  
1.6  
* #### pollLast  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") pollLast()  
Retrieves and removes the last element of this list, or returns `null` if this list is empty.  
Specified by:  
`[pollLast](../../java/util/Deque.html#pollLast--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the last element of this list, or `null` if this list is empty  
Since:  
1.6  
* #### push  
public void push([E](../../java/util/LinkedList.html "type parameter in LinkedList") e)  
Pushes an element onto the stack represented by this list. In other words, inserts the element at the front of this list.  
This method is equivalent to [addFirst(E)](../../java/util/LinkedList.html#addFirst-E-).  
Specified by:  
`[push](../../java/util/Deque.html#push-E-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`e` \- the element to push  
Since:  
1.6  
* #### pop  
public [E](../../java/util/LinkedList.html "type parameter in LinkedList") pop()  
Pops an element from the stack represented by this list. In other words, removes and returns the first element of this list.  
This method is equivalent to [removeFirst()](../../java/util/LinkedList.html#removeFirst--).  
Specified by:  
`[pop](../../java/util/Deque.html#pop--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
the element at the front of this list (which is the top of the stack represented by this list)  
Throws:  
`[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if this list is empty  
Since:  
1.6  
* #### removeFirstOccurrence  
public boolean removeFirstOccurrence([Object](../../java/lang/Object.html "class in java.lang") o)  
Removes the first occurrence of the specified element in this list (when traversing the list from head to tail). If the list does not contain the element, it is unchanged.  
Specified by:  
`[removeFirstOccurrence](../../java/util/Deque.html#removeFirstOccurrence-java.lang.Object-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`o` \- element to be removed from this list, if present  
Returns:  
`true` if the list contained the specified element  
Since:  
1.6  
* #### removeLastOccurrence  
public boolean removeLastOccurrence([Object](../../java/lang/Object.html "class in java.lang") o)  
Removes the last occurrence of the specified element in this list (when traversing the list from head to tail). If the list does not contain the element, it is unchanged.  
Specified by:  
`[removeLastOccurrence](../../java/util/Deque.html#removeLastOccurrence-java.lang.Object-)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`o` \- element to be removed from this list, if present  
Returns:  
`true` if the list contained the specified element  
Since:  
1.6  
* #### listIterator  
public [ListIterator](../../java/util/ListIterator.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")> listIterator(int index)  
Returns a list-iterator of the elements in this list (in proper sequence), starting at the specified position in the list. Obeys the general contract of `List.listIterator(int)`.  
 The list-iterator is _fail-fast_: if the list is structurally modified at any time after the Iterator is created, in any way except through the list-iterator's own `remove` or `add` methods, the list-iterator will throw a`ConcurrentModificationException`. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.  
Specified by:  
`[listIterator](../../java/util/List.html#listIterator-int-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[listIterator](../../java/util/AbstractSequentialList.html#listIterator-int-)` in class `[AbstractSequentialList](../../java/util/AbstractSequentialList.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Parameters:  
`index` \- index of the first element to be returned from the list-iterator (by a call to `next`)  
Returns:  
a ListIterator of the elements in this list (in proper sequence), starting at the specified position in the list  
Throws:  
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
See Also:  
[List.listIterator(int)](../../java/util/List.html#listIterator-int-)  
* #### descendingIterator  
public [Iterator](../../java/util/Iterator.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")> descendingIterator()  
Description copied from interface: `[Deque](../../java/util/Deque.html#descendingIterator--)`  
Returns an iterator over the elements in this deque in reverse sequential order. The elements will be returned in order from last (tail) to first (head).  
Specified by:  
`[descendingIterator](../../java/util/Deque.html#descendingIterator--)` in interface `[Deque](../../java/util/Deque.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
an iterator over the elements in this deque in reverse sequence  
Since:  
1.6  
* #### clone  
public [Object](../../java/lang/Object.html "class in java.lang") clone()  
Returns a shallow copy of this `LinkedList`. (The elements themselves are not cloned.)  
Overrides:  
`[clone](../../java/lang/Object.html#clone--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
Returns:  
a shallow copy of this `LinkedList` instance  
See Also:  
[Cloneable](../../java/lang/Cloneable.html "interface in java.lang")  
* #### toArray  
public [Object](../../java/lang/Object.html "class in java.lang")[] toArray()  
Returns an array containing all of the elements in this list in proper sequence (from first to last element).  
The returned array will be "safe" in that no references to it are maintained by this list. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.  
This method acts as bridge between array-based and collection-based APIs.  
Specified by:  
`[toArray](../../java/util/Collection.html#toArray--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[toArray](../../java/util/List.html#toArray--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[toArray](../../java/util/AbstractCollection.html#toArray--)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Returns:  
an array containing all of the elements in this list in proper sequence  
See Also:  
[Arrays.asList(Object\[\])](../../java/util/Arrays.html#asList-T...-)  
* #### toArray  
public <T> T[] toArray(T[] a)  
Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list.  
If the list fits in the specified array with room to spare (i.e., the array has more elements than the list), the element in the array immediately following the end of the list is set to `null`. (This is useful in determining the length of the list _only_ if the caller knows that the list does not contain any null elements.)  
Like the [toArray()](../../java/util/LinkedList.html#toArray--) method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.  
Suppose `x` is a list known to contain only strings. The following code can be used to dump the list into a newly allocated array of `String`:  
     String[] y = x.toArray(new String[0]);  
 Note that `toArray(new Object[0])` is identical in function to`toArray()`.  
Specified by:  
`[toArray](../../java/util/Collection.html#toArray-T:A-)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[toArray](../../java/util/List.html#toArray-T:A-)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Overrides:  
`[toArray](../../java/util/AbstractCollection.html#toArray-T:A-)` in class `[AbstractCollection](../../java/util/AbstractCollection.html "class in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Type Parameters:  
`T` \- the runtime type of the array to contain the collection  
Parameters:  
`a` \- the array into which the elements of the list are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.  
Returns:  
an array containing the elements of the list  
Throws:  
`[ArrayStoreException](../../java/lang/ArrayStoreException.html "class in java.lang")` \- if the runtime type of the specified array is not a supertype of the runtime type of every element in this list  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified array is null  
* #### spliterator  
public [Spliterator](../../java/util/Spliterator.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")> spliterator()  
Specified by:  
`[spliterator](../../java/util/Collection.html#spliterator--)` in interface `[Collection](../../java/util/Collection.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[spliterator](../../java/lang/Iterable.html#spliterator--)` in interface `[Iterable](../../java/lang/Iterable.html "interface in java.lang")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Specified by:  
`[spliterator](../../java/util/List.html#spliterator--)` in interface `[List](../../java/util/List.html "interface in java.util")<[E](../../java/util/LinkedList.html "type parameter in LinkedList")>`  
Implementation Note:  
The `Spliterator` additionally reports [Spliterator.SUBSIZED](../../java/util/Spliterator.html#SUBSIZED) and implements `trySplit` to permit limited parallelism..  
Returns:  
a `Spliterator` over the elements in this list  
Since:  
1.8

LinkedList (Java SE 9 & JDK 9 ) (original) (raw)

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