public interface List<E>

ExtendsCollection<E>, Iterable<E>

Known subtypesAbstractList, AbstractSequentialList, ArrayList, LinkedList, Stack, Vector

A List is a collection which maintains an ordering for its elements. Every element in the List has an index. Each element can thus be accessed by its index, with the first index being zero. Normally, Lists allow duplicate elements, as compared to Sets, where elements have to be unique.

Methods

public abstract void add(int location, E object)Inserts the specified object into this List at the specified location.
public abstract boolean add(E object)Adds the specified object at the end of this List.
public abstract boolean addAll(int location, Collection<? extends E> collection)Inserts the objects in the specified collection at the specified location in this List.
public abstract boolean addAll(Collection<? extends E> collection)Adds the objects in the specified collection to the end of this List.
public abstract void clear()Removes all elements from this List, leaving it empty.
public abstract boolean contains(Object object)Tests whether this List contains the specified object.
public abstract boolean containsAll(Collection<?> collection)Tests whether this List contains all objects contained in the specified collection.
public abstract boolean equals(Object object)Compares the given object with the List, and returns true if they represent the same object using a class specific comparison.
public abstract E get(int location)Returns the element at the specified location in this List.
public abstract int hashCode()Returns the hash code for this List.
public abstract int indexOf(Object object)Searches this List for the specified object and returns the index of the first occurrence.
public abstract boolean isEmpty()Returns whether this List contains no elements.
public abstract Iterator<E> iterator()Returns an iterator on the elements of this List.
public abstract int lastIndexOf(Object object)Searches this List for the specified object and returns the index of the last occurrence.
public abstract ListIterator<E> listIterator()Returns a List iterator on the elements of this List.
public abstract ListIterator<E> listIterator(int location)Returns a list iterator on the elements of this List.
public abstract E remove(int location)Removes the object at the specified location from this List.
public abstract boolean remove(Object object)Removes the first occurrence of the specified object from this List.
public abstract boolean removeAll(Collection<?> collection)Removes all occurrences in this List of each object in the specified collection.
public abstract boolean retainAll(Collection<?> collection)Removes all objects from this List that are not contained in the specified collection.
public abstract E set(int location, E object)Replaces the element at the specified location in this List with the specified object.
public abstract int size()Returns the number of elements in this List.
public abstract List<E> subList(int start, int end)Returns a List of the specified portion of this List from the given start index to the end index minus one.
public abstract Object[] toArray()Returns an array containing all elements contained in this List.
public abstract <T> T[] toArray(T[] array)Returns an array containing all elements contained in this List.
public default void replaceAll(UnaryOperator<E> operator)Replaces each element of this list with the result of applying the operator to that element.
public default void sort(Comparator<? super E> c)Sorts this list according to the order induced by the specified Comparator.

Inherited methods

From Collection

removeIf

From Iterable

forEach

Method details

add

public abstract void add(int location, E object)
Inserts the specified object into this List at the specified location. The object is inserted before the current element at the specified location. If the location is equal to the size of this List, the object is added at the end. If the location is smaller than the size of this List, then all elements beyond the specified location are moved by one position towards the end of the List.

Parameters

location int
the index at which to insert.
object E
the object to add.

Throws

UnsupportedOperationException
if adding to this List is not supported.
ClassCastException
if the class of the object is inappropriate for this List.
IllegalArgumentException
if the object cannot be added to this List.
IndexOutOfBoundsException
if location size()

add

public abstract boolean add(E object)
Adds the specified object at the end of this List.

Parameters

object E
the object to add.

Returns

always true.

Throws

UnsupportedOperationException
if adding to this List is not supported.
ClassCastException
if the class of the object is inappropriate for this List.
IllegalArgumentException
if the object cannot be added to this List.

addAll

public abstract boolean addAll(int location, Collection<? extends E> collection)
Inserts the objects in the specified collection at the specified location in this List. The objects are added in the order they are returned from the collection’s iterator.

Parameters

location int
the index at which to insert.
collection Collection<? extends E>
the collection of objects to be inserted.

Returns

true if this List has been modified through the insertion, false otherwise (i.e. if the passed collection was empty).

Throws

UnsupportedOperationException
if adding to this List is not supported.
ClassCastException
if the class of an object is inappropriate for this List.
IllegalArgumentException
if an object cannot be added to this List.
IndexOutOfBoundsException
if location size()

addAll

public abstract boolean addAll(Collection<? extends E> collection)
Adds the objects in the specified collection to the end of this List. The objects are added in the order in which they are returned from the collection’s iterator.

Parameters

collection Collection<? extends E>
the collection of objects.

Returns

true if this List is modified, false otherwise (i.e. if the passed collection was empty).

Throws

UnsupportedOperationException
if adding to this List is not supported.
ClassCastException
if the class of an object is inappropriate for this List.
IllegalArgumentException
if an object cannot be added to this List.

clear

public abstract void clear()
Removes all elements from this List, leaving it empty.

Throws

UnsupportedOperationException
if removing from this List is not supported.

See also

contains

public abstract boolean contains(Object object)
Tests whether this List contains the specified object.

Parameters

object Object
the object to search for.

Returns

true if object is an element of this List, false otherwise

containsAll

public abstract boolean containsAll(Collection<?> collection)
Tests whether this List contains all objects contained in the specified collection.

Parameters

collection Collection<?>
the collection of objects

Returns

true if all objects in the specified collection are elements of this List, false otherwise.

equals

public abstract boolean equals(Object object)
Compares the given object with the List, and returns true if they represent the same object using a class specific comparison. For Lists, this means that they contain the same elements in exactly the same order.

Parameters

object Object
the object to compare with this object.

Returns

boolean true if the object is the same as this object, and false if it is different from this object.

See also

get

public abstract E get(int location)
Returns the element at the specified location in this List.

Parameters

location int
the index of the element to return.

Returns

the element at the specified location.

Throws

IndexOutOfBoundsException
if location = size()

hashCode

public abstract int hashCode()
Returns the hash code for this List. It is calculated by taking each element’ hashcode and its position in the List into account.

Returns

the hash code of the List.

indexOf

public abstract int indexOf(Object object)
Searches this List for the specified object and returns the index of the first occurrence.

Parameters

object Object
the object to search for.

Returns

the index of the first occurrence of the object or -1 if the object was not found.

isEmpty

public abstract boolean isEmpty()
Returns whether this List contains no elements.

Returns

true if this List has no elements, false otherwise.

See also

iterator

public abstract Iterator<E> iterator()
Returns an iterator on the elements of this List. The elements are iterated in the same order as they occur in the List.

Returns

an iterator on the elements of this List.

See also

lastIndexOf

public abstract int lastIndexOf(Object object)
Searches this List for the specified object and returns the index of the last occurrence.

Parameters

object Object
the object to search for.

Returns

the index of the last occurrence of the object, or -1 if the object was not found.

listIterator

public abstract ListIterator<E> listIterator()
Returns a List iterator on the elements of this List. The elements are iterated in the same order that they occur in the List.

Returns

a List iterator on the elements of this List

See also

listIterator

public abstract ListIterator<E> listIterator(int location)
Returns a list iterator on the elements of this List. The elements are iterated in the same order as they occur in the List. The iteration starts at the specified location.

Parameters

location int
the index at which to start the iteration.

Returns

a list iterator on the elements of this List.

Throws

IndexOutOfBoundsException
if location size()

See also

remove

public abstract E remove(int location)
Removes the object at the specified location from this List.

Parameters

location int
the index of the object to remove.

Returns

the removed object.

Throws

UnsupportedOperationException
if removing from this List is not supported.
IndexOutOfBoundsException
if location = size()

remove

public abstract boolean remove(Object object)
Removes the first occurrence of the specified object from this List.

Parameters

object Object
the object to remove.

Returns

true if this List was modified by this operation, false otherwise.

Throws

UnsupportedOperationException
if removing from this List is not supported.

removeAll

public abstract boolean removeAll(Collection<?> collection)
Removes all occurrences in this List of each object in the specified collection.

Parameters

collection Collection<?>
the collection of objects to remove.

Returns

true if this List is modified, false otherwise.

Throws

UnsupportedOperationException
if removing from this List is not supported.

retainAll

public abstract boolean retainAll(Collection<?> collection)
Removes all objects from this List that are not contained in the specified collection.

Parameters

collection Collection<?>
the collection of objects to retain.

Returns

true if this List is modified, false otherwise.

Throws

UnsupportedOperationException
if removing from this List is not supported.

set

public abstract E set(int location, E object)
Replaces the element at the specified location in this List with the specified object. This operation does not change the size of the List.

Parameters

location int
the index at which to put the specified object.
object E
the object to insert.

Returns

the previous element at the index.

Throws

UnsupportedOperationException
if replacing elements in this List is not supported.
ClassCastException
if the class of an object is inappropriate for this List.
IllegalArgumentException
if an object cannot be added to this List.
IndexOutOfBoundsException
if location = size()

size

public abstract int size()
Returns the number of elements in this List.

Returns

the number of elements in this List.

subList

public abstract List<E> subList(int start, int end)
Returns a List of the specified portion of this List from the given start index to the end index minus one. The returned List is backed by this List so changes to it are reflected by the other.

Parameters

start int
the index at which to start the sublist.
end int
the index one past the end of the sublist.

Returns

a list of a portion of this List.

Throws

IndexOutOfBoundsException
if start end or end > size()

toArray

public abstract Object[] toArray()
Returns an array containing all elements contained in this List.

Returns

an array of the elements from this List.

toArray

public abstract <T> T[] toArray(T[] array)
Returns an array containing all elements contained in this List. If the specified array is large enough to hold the elements, the specified array is used, otherwise an array of the same type is created. If the specified array is used and is larger than this List, the array element following the collection elements is set to null.

Parameters

array T[]
the array.

Returns

an array of the elements from this List.

Throws

ArrayStoreException
if the type of an element in this List cannot be stored in the type of the specified array.

replaceAll

public default void replaceAll(UnaryOperator<E> operator)
Replaces each element of this list with the result of applying the operator to that element. Stubbed in the CLDC11 subset; the actual implementation comes from the platform’s JDK at runtime.

sort

public default void sort(Comparator<? super E> c)
Sorts this list according to the order induced by the specified Comparator. Stubbed in the CLDC11 subset; the actual implementation comes from the platform’s JDK at runtime.