Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Fields](https://developer.android.com/reference/java/util/AbstractList#lfields) \| [Protected Ctors](https://developer.android.com/reference/java/util/AbstractList#proctors) \| [Methods](https://developer.android.com/reference/java/util/AbstractList#pubmethods) \| [Protected Methods](https://developer.android.com/reference/java/util/AbstractList#promethods) \| [Inherited Methods](https://developer.android.com/reference/java/util/AbstractList#inhmethods)

# AbstractList

` public abstract class AbstractList `   
` ` ` extends https://developer.android.com/reference/java/util/AbstractCollection<E> ` ` implements https://developer.android.com/reference/java/util/List<E> `

|---|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) |||
| ↳ | [java.util.AbstractCollection](https://developer.android.com/reference/java/util/AbstractCollection)\<E\> ||
|   | ↳ | java.util.AbstractList\<E\> |

Known direct subclasses [AbstractSequentialList](https://developer.android.com/reference/java/util/AbstractSequentialList)\<E\>, [ArrayList](https://developer.android.com/reference/java/util/ArrayList)\<E\>, [Vector](https://developer.android.com/reference/java/util/Vector)\<E\> [AbstractSequentialList](https://developer.android.com/reference/java/util/AbstractSequentialList)\<E\> This class provides a skeletal implementation of the `List` interface to minimize the effort required to implement this interface backed by a "sequential access" data store (such as a linked list). [ArrayList](https://developer.android.com/reference/java/util/ArrayList)\<E\> Resizable-array implementation of the `List` interface. [Vector](https://developer.android.com/reference/java/util/Vector)\<E\> The `Vector` class implements a growable array of objects. Known indirect subclasses [LinkedList](https://developer.android.com/reference/java/util/LinkedList)\<E\>, [Stack](https://developer.android.com/reference/java/util/Stack)\<E\> [LinkedList](https://developer.android.com/reference/java/util/LinkedList)\<E\> Doubly-linked list implementation of the `List` and `Deque` interfaces. [Stack](https://developer.android.com/reference/java/util/Stack)\<E\> The `Stack` class represents a last-in-first-out (LIFO) stack of objects.   

*** ** * ** ***

This class provides a skeletal implementation of the `https://developer.android.com/reference/java/util/List` interface to minimize the effort required to implement this interface backed by a "random access" data store (such as an array). For sequential access data (such as a linked list), `https://developer.android.com/reference/java/util/AbstractSequentialList` should be used in preference to this class.

To implement an unmodifiable list, the programmer needs only to extend this class and provide implementations for the `https://developer.android.com/reference/java/util/AbstractList#get(int)` and `https://developer.android.com/reference/java/util/List#size()` methods.

To implement a modifiable list, the programmer must additionally override the `https://developer.android.com/reference/java/util/AbstractList#set(int,%20E)` method (which otherwise throws an `UnsupportedOperationException`). If the list is variable-size the programmer must additionally override the `https://developer.android.com/reference/java/util/AbstractList#add(int,%20E)` and `https://developer.android.com/reference/java/util/AbstractList#remove(int)` methods.

The programmer should generally provide a void (no argument) and collection constructor, as per the recommendation in the `https://developer.android.com/reference/java/util/Collection` interface specification.

Unlike the other abstract collection implementations, the programmer does *not* have to provide an iterator implementation; the iterator and list iterator are implemented by this class, on top of the "random access" methods: `https://developer.android.com/reference/java/util/AbstractList#get(int)`, `https://developer.android.com/reference/java/util/AbstractList#set(int,%20E)`, `https://developer.android.com/reference/java/util/AbstractList#add(int,%20E)` and `https://developer.android.com/reference/java/util/AbstractList#remove(int)`.

The documentation for each non-abstract method in this class describes its implementation in detail. Each of these methods may be overridden if the collection being implemented admits a more efficient implementation.

This class is a member of the [Java Collections Framework](https://reference/java/util/package-summary.html#CollectionsFramework).

## Summary

| ### Fields ||
|---|---|
| ` protected int` | `https://developer.android.com/reference/java/util/AbstractList#modCount` The number of times this list has been *structurally modified*. |

| ### Protected constructors ||
|---|---|
| ` https://developer.android.com/reference/java/util/AbstractList#AbstractList()() ` Sole constructor. |

| ### Public methods ||
|---|---|
| ` void` | ` https://developer.android.com/reference/java/util/AbstractList#add(int,%20E)(int index, E element) ` Inserts the specified element at the specified position in this list (optional operation). |
| ` boolean` | ` https://developer.android.com/reference/java/util/AbstractList#add(E)(E e) ` Appends the specified element to the end of this list (optional operation). |
| ` boolean` | ` https://developer.android.com/reference/java/util/AbstractList#addAll(int,%20java.util.Collection<?%20extends%20E>)(int index, https://developer.android.com/reference/java/util/Collection<? extends E> c) ` Inserts all of the elements in the specified collection into this list at the specified position (optional operation). |
| ` void` | ` https://developer.android.com/reference/java/util/AbstractList#clear()() ` Removes all of the elements from this list (optional operation). |
| ` boolean` | ` https://developer.android.com/reference/java/util/AbstractList#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Compares the specified object with this list for equality. |
| ` abstract E` | ` https://developer.android.com/reference/java/util/AbstractList#get(int)(int index) ` Returns the element at the specified position in this list. |
| ` int` | ` https://developer.android.com/reference/java/util/AbstractList#hashCode()() ` Returns the hash code value for this list. |
| ` int` | ` https://developer.android.com/reference/java/util/AbstractList#indexOf(java.lang.Object)(https://developer.android.com/reference/java/lang/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. |
| ` https://developer.android.com/reference/java/util/Iterator<E>` | ` https://developer.android.com/reference/java/util/AbstractList#iterator()() ` Returns an iterator over the elements in this list in proper sequence. |
| ` int` | ` https://developer.android.com/reference/java/util/AbstractList#lastIndexOf(java.lang.Object)(https://developer.android.com/reference/java/lang/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. |
| ` https://developer.android.com/reference/java/util/ListIterator<E>` | ` https://developer.android.com/reference/java/util/AbstractList#listIterator(int)(int index) ` Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. |
| ` https://developer.android.com/reference/java/util/ListIterator<E>` | ` https://developer.android.com/reference/java/util/AbstractList#listIterator()() ` Returns a list iterator over the elements in this list (in proper sequence). |
| ` E` | ` https://developer.android.com/reference/java/util/AbstractList#remove(int)(int index) ` Removes the element at the specified position in this list (optional operation). |
| ` E` | ` https://developer.android.com/reference/java/util/AbstractList#set(int,%20E)(int index, E element) ` Replaces the element at the specified position in this list with the specified element (optional operation). |
| ` https://developer.android.com/reference/java/util/List<E>` | ` https://developer.android.com/reference/java/util/AbstractList#subList(int,%20int)(int fromIndex, int toIndex) ` Returns a view of the portion of this list between the specified `fromIndex`, inclusive, and `toIndex`, exclusive. |

| ### Protected methods ||
|---|---|
| ` void` | ` https://developer.android.com/reference/java/util/AbstractList#removeRange(int,%20int)(int fromIndex, int toIndex) ` Removes from this list all of the elements whose index is between `fromIndex`, inclusive, and `toIndex`, exclusive. |

### Inherited methods

From class ` https://developer.android.com/reference/java/util/AbstractCollection ` ` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#add(E)(E e) `

Ensures that this collection contains the specified element (optional operation).
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#addAll(java.util.Collection<?%20extends%20E>)(https://developer.android.com/reference/java/util/Collection<? extends E> c) `

Adds all of the elements in the specified collection to this collection (optional operation).
` void` ` https://developer.android.com/reference/java/util/AbstractCollection#clear()() `

Removes all of the elements from this collection (optional operation).
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Returns `true` if this collection contains the specified element.
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#containsAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Returns `true` if this collection contains all of the elements in the specified collection.
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#isEmpty()() `

Returns `true` if this collection contains no elements.
` abstract https://developer.android.com/reference/java/util/Iterator<E>` ` https://developer.android.com/reference/java/util/AbstractCollection#iterator()() `

Returns an iterator over the elements contained in this collection.
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Removes a single instance of the specified element from this collection, if it is present (optional operation).
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#removeAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Removes all of this collection's elements that are also contained in the specified collection (optional operation).
` boolean` ` https://developer.android.com/reference/java/util/AbstractCollection#retainAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Retains only the elements in this collection that are contained in the specified collection (optional operation).
` abstract int` ` https://developer.android.com/reference/java/util/AbstractCollection#size()() `

Returns the number of elements in this collection.
` <T> T[]` ` https://developer.android.com/reference/java/util/AbstractCollection#toArray(T[])(T[] a) `

Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.
` https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/util/AbstractCollection#toArray()() `

Returns an array containing all of the elements in this collection.
` https://developer.android.com/reference/java/lang/String` ` https://developer.android.com/reference/java/util/AbstractCollection#toString()() `

Returns a string representation of this collection.
From class ` https://developer.android.com/reference/java/lang/Object ` ` https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/lang/Object#clone()() `

Creates and returns a copy of this object.
` boolean` ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) `

Indicates whether some other object is "equal to" this one.
` void` ` https://developer.android.com/reference/java/lang/Object#finalize()() `

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
` final https://developer.android.com/reference/java/lang/Class<?>` ` https://developer.android.com/reference/java/lang/Object#getClass()() `

Returns the runtime class of this `Object`.
` int` ` https://developer.android.com/reference/java/lang/Object#hashCode()() `

Returns a hash code value for the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#notify()() `

Wakes up a single thread that is waiting on this object's monitor.
` final void` ` https://developer.android.com/reference/java/lang/Object#notifyAll()() `

Wakes up all threads that are waiting on this object's monitor.
` https://developer.android.com/reference/java/lang/String` ` https://developer.android.com/reference/java/lang/Object#toString()() `

Returns a string representation of the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait()() `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*.
From interface ` https://developer.android.com/reference/java/util/Collection ` ` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#add(E)(E e) `

Ensures that this collection contains the specified element (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#addAll(java.util.Collection<?%20extends%20E>)(https://developer.android.com/reference/java/util/Collection<? extends E> c) `

Adds all of the elements in the specified collection to this collection (optional operation).
` abstract void` ` https://developer.android.com/reference/java/util/Collection#clear()() `

Removes all of the elements from this collection (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Returns `true` if this collection contains the specified element.
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#containsAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Returns `true` if this collection contains all of the elements in the specified collection.
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Compares the specified object with this collection for equality.
` abstract int` ` https://developer.android.com/reference/java/util/Collection#hashCode()() `

Returns the hash code value for this collection.
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#isEmpty()() `

Returns `true` if this collection contains no elements.
` abstract https://developer.android.com/reference/java/util/Iterator<E>` ` https://developer.android.com/reference/java/util/Collection#iterator()() `

Returns an iterator over the elements in this collection.
` default https://developer.android.com/reference/java/util/stream/Stream<E>` ` https://developer.android.com/reference/java/util/Collection#parallelStream()() `

Returns a possibly parallel `Stream` with this collection as its source.
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Removes a single instance of the specified element from this collection, if it is present (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#removeAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Removes all of this collection's elements that are also contained in the specified collection (optional operation).
` default boolean` ` https://developer.android.com/reference/java/util/Collection#removeIf(java.util.function.Predicate<?%20super%20E>)(https://developer.android.com/reference/java/util/function/Predicate<? super E> filter) `

Removes all of the elements of this collection that satisfy the given predicate (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/Collection#retainAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Retains only the elements in this collection that are contained in the specified collection (optional operation).
` abstract int` ` https://developer.android.com/reference/java/util/Collection#size()() `

Returns the number of elements in this collection.
` default https://developer.android.com/reference/java/util/Spliterator<E>` ` https://developer.android.com/reference/java/util/Collection#spliterator()() `

Creates a `https://developer.android.com/reference/java/util/Spliterator` over the elements in this collection.
` default https://developer.android.com/reference/java/util/stream/Stream<E>` ` https://developer.android.com/reference/java/util/Collection#stream()() `

Returns a sequential `Stream` with this collection as its source.
` abstract <T> T[]` ` https://developer.android.com/reference/java/util/Collection#toArray(T[])(T[] a) `

Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.
` abstract https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/util/Collection#toArray()() `

Returns an array containing all of the elements in this collection.
` default <T> T[]` ` https://developer.android.com/reference/java/util/Collection#toArray(java.util.function.IntFunction<T[]>)(https://developer.android.com/reference/java/util/function/IntFunction<T[]> generator) `

Returns an array containing all of the elements in this collection, using the provided `generator` function to allocate the returned array.
From interface ` https://developer.android.com/reference/java/util/List ` ` abstract boolean` ` https://developer.android.com/reference/java/util/List#add(E)(E e) `

Appends the specified element to the end of this list (optional operation).
` abstract void` ` https://developer.android.com/reference/java/util/List#add(int,%20E)(int index, E element) `

Inserts the specified element at the specified position in this list (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/List#addAll(java.util.Collection<?%20extends%20E>)(https://developer.android.com/reference/java/util/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 (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/List#addAll(int,%20java.util.Collection<?%20extends%20E>)(int index, https://developer.android.com/reference/java/util/Collection<? extends E> c) `

Inserts all of the elements in the specified collection into this list at the specified position (optional operation).
` default void` ` https://developer.android.com/reference/java/util/List#addFirst(E)(E e) `

Adds an element as the first element of this collection (optional operation).
` default void` ` https://developer.android.com/reference/java/util/List#addLast(E)(E e) `

Adds an element as the last element of this collection (optional operation).
` abstract void` ` https://developer.android.com/reference/java/util/List#clear()() `

Removes all of the elements from this list (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/List#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Returns `true` if this list contains the specified element.
` abstract boolean` ` https://developer.android.com/reference/java/util/List#containsAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Returns `true` if this list contains all of the elements of the specified collection.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#copyOf(java.util.Collection<?%20extends%20E>)(https://developer.android.com/reference/java/util/Collection<? extends E> coll) `

Returns an [unmodifiable List](https://developer.android.com/reference/java/util/AbstractList#unmodifiable) containing the elements of the given Collection, in its iteration order.
` abstract boolean` ` https://developer.android.com/reference/java/util/List#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Compares the specified object with this list for equality.
` abstract E` ` https://developer.android.com/reference/java/util/List#get(int)(int index) `

Returns the element at the specified position in this list.
` default E` ` https://developer.android.com/reference/java/util/List#getFirst()() `

Gets the first element of this collection.
` default E` ` https://developer.android.com/reference/java/util/List#getLast()() `

Gets the last element of this collection.
` abstract int` ` https://developer.android.com/reference/java/util/List#hashCode()() `

Returns the hash code value for this list.
` abstract int` ` https://developer.android.com/reference/java/util/List#indexOf(java.lang.Object)(https://developer.android.com/reference/java/lang/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.
` abstract boolean` ` https://developer.android.com/reference/java/util/List#isEmpty()() `

Returns `true` if this list contains no elements.
` abstract https://developer.android.com/reference/java/util/Iterator<E>` ` https://developer.android.com/reference/java/util/List#iterator()() `

Returns an iterator over the elements in this list in proper sequence.
` abstract int` ` https://developer.android.com/reference/java/util/List#lastIndexOf(java.lang.Object)(https://developer.android.com/reference/java/lang/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.
` abstract https://developer.android.com/reference/java/util/ListIterator<E>` ` https://developer.android.com/reference/java/util/List#listIterator(int)(int index) `

Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.
` abstract https://developer.android.com/reference/java/util/ListIterator<E>` ` https://developer.android.com/reference/java/util/List#listIterator()() `

Returns a list iterator over the elements in this list (in proper sequence).
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E)(E e1, E e2, E e3) `

Returns an unmodifiable list containing three elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E,%20E,%20E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9) `

Returns an unmodifiable list containing nine elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4, E e5) `

Returns an unmodifiable list containing five elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4, E e5, E e6) `

Returns an unmodifiable list containing six elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E,%20E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8) `

Returns an unmodifiable list containing eight elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E[])(E... elements) `

Returns an unmodifiable list containing an arbitrary number of elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of()() `

Returns an unmodifiable list containing zero elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E,%20E,%20E,%20E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10) `

Returns an unmodifiable list containing ten elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E)(E e1, E e2) `

Returns an unmodifiable list containing two elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4, E e5, E e6, E e7) `

Returns an unmodifiable list containing seven elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E,%20E,%20E,%20E)(E e1, E e2, E e3, E e4) `

Returns an unmodifiable list containing four elements.
` static <E> https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#of(E)(E e1) `

Returns an unmodifiable list containing one element.
` abstract E` ` https://developer.android.com/reference/java/util/List#remove(int)(int index) `

Removes the element at the specified position in this list (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/List#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Removes the first occurrence of the specified element from this list, if it is present (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/List#removeAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Removes from this list all of its elements that are contained in the specified collection (optional operation).
` default E` ` https://developer.android.com/reference/java/util/List#removeFirst()() `

Removes and returns the first element of this collection (optional operation).
` default E` ` https://developer.android.com/reference/java/util/List#removeLast()() `

Removes and returns the last element of this collection (optional operation).
` default void` ` https://developer.android.com/reference/java/util/List#replaceAll(java.util.function.UnaryOperator<E>)(https://developer.android.com/reference/java/util/function/UnaryOperator<E> operator) `

Replaces each element of this list with the result of applying the operator to that element (optional operation).
` abstract boolean` ` https://developer.android.com/reference/java/util/List#retainAll(java.util.Collection<?>)(https://developer.android.com/reference/java/util/Collection<?> c) `

Retains only the elements in this list that are contained in the specified collection (optional operation).
` default https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#reversed()() `

Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/Collection#view) of this collection.
` abstract E` ` https://developer.android.com/reference/java/util/List#set(int,%20E)(int index, E element) `

Replaces the element at the specified position in this list with the specified element (optional operation).
` abstract int` ` https://developer.android.com/reference/java/util/List#size()() `

Returns the number of elements in this list.
` default void` ` https://developer.android.com/reference/java/util/List#sort(java.util.Comparator<?%20super%20E>)(https://developer.android.com/reference/java/util/Comparator<? super E> c) `

Sorts this list according to the order induced by the specified `https://developer.android.com/reference/java/util/Comparator` (optional operation).
` default https://developer.android.com/reference/java/util/Spliterator<E>` ` https://developer.android.com/reference/java/util/List#spliterator()() `

Creates a `https://developer.android.com/reference/java/util/Spliterator` over the elements in this list.
` abstract https://developer.android.com/reference/java/util/List<E>` ` https://developer.android.com/reference/java/util/List#subList(int,%20int)(int fromIndex, int toIndex) `

Returns a view of the portion of this list between the specified `fromIndex`, inclusive, and `toIndex`, exclusive.
` abstract https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/util/List#toArray()() `

Returns an array containing all of the elements in this list in proper sequence (from first to last element).
` abstract <T> T[]` ` https://developer.android.com/reference/java/util/List#toArray(T[])(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.
From interface ` https://developer.android.com/reference/java/lang/Iterable ` ` default void` ` https://developer.android.com/reference/java/lang/Iterable#forEach(java.util.function.Consumer<?%20super%20T>)(https://developer.android.com/reference/java/util/function/Consumer<? super T> action) `

Performs the given action for each element of the `Iterable` until all elements have been processed or the action throws an exception.
` abstract https://developer.android.com/reference/java/util/Iterator<E>` ` https://developer.android.com/reference/java/lang/Iterable#iterator()() `

Returns an iterator over elements of type `T`.
` default https://developer.android.com/reference/java/util/Spliterator<E>` ` https://developer.android.com/reference/java/lang/Iterable#spliterator()() `

Creates a `https://developer.android.com/reference/java/util/Spliterator` over the elements described by this `Iterable`.
From interface ` https://developer.android.com/reference/java/util/SequencedCollection ` ` default void` ` https://developer.android.com/reference/java/util/SequencedCollection#addFirst(E)(E e) `

Adds an element as the first element of this collection (optional operation).
` default void` ` https://developer.android.com/reference/java/util/SequencedCollection#addLast(E)(E e) `

Adds an element as the last element of this collection (optional operation).
` default E` ` https://developer.android.com/reference/java/util/SequencedCollection#getFirst()() `

Gets the first element of this collection.
` default E` ` https://developer.android.com/reference/java/util/SequencedCollection#getLast()() `

Gets the last element of this collection.
` default E` ` https://developer.android.com/reference/java/util/SequencedCollection#removeFirst()() `

Removes and returns the first element of this collection (optional operation).
` default E` ` https://developer.android.com/reference/java/util/SequencedCollection#removeLast()() `

Removes and returns the last element of this collection (optional operation).
` abstract https://developer.android.com/reference/java/util/SequencedCollection<E>` ` https://developer.android.com/reference/java/util/SequencedCollection#reversed()() `

Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/Collection#view) of this collection.

## Fields

### modCount

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
protected int modCount
```

The number of times this list has been *structurally modified*. Structural modifications are those that change the size of the list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.

This field is used by the iterator and list iterator implementation returned by the `iterator` and `listIterator` methods. If the value of this field changes unexpectedly, the iterator (or list iterator) will throw a `ConcurrentModificationException` in response to the `next`, `remove`, `previous`, `set` or `add` operations. This provides *fail-fast* behavior, rather than non-deterministic behavior in the face of concurrent modification during iteration.

**Use of this field by subclasses is optional.** If a subclass wishes to provide fail-fast iterators (and list iterators), then it merely has to increment this field in its `add(int, E)` and `remove(int)` methods (and any other methods that it overrides that result in structural modifications to the list). A single call to `add(int, E)` or `remove(int)` must add no more than one to this field, or the iterators (and list iterators) will throw bogus `ConcurrentModificationExceptions`. If an implementation does not wish to provide fail-fast iterators, this field may be ignored.

<br />

## Protected constructors

### AbstractList

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
protected AbstractList ()
```

Sole constructor. (For invocation by subclass constructors, typically implicit.)

<br />

## Public methods

### add

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void add (int index, 
                E element)
```

Inserts the specified element at the specified position in this list (optional operation). Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

<br />

##### Implementation Requirements:

- This implementation always throws an `UnsupportedOperationException`.

| Parameters ||
|---|---|
| `index` | `int`: index at which the specified element is to be inserted <br /> |
| `element` | `E`: element to be inserted <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` |   |

### add

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean add (E e)
```

Appends the specified element to the end of this list (optional operation).

Lists that support this operation may place limitations on what elements may be added to this list. In particular, some lists will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. List classes should clearly specify in their documentation any restrictions on what elements may be added.

<br />

##### Implementation Requirements:

- This implementation calls `add(size(), e)`.

  Note that this implementation throws an `UnsupportedOperationException` unless `https://developer.android.com/reference/java/util/AbstractList#add(int,%20E)` is overridden.

| Parameters ||
|---|---|
| `e` | `E`: element to be appended to this list <br /> |

| Returns ||
|---|---|
| `boolean` | `true` (as specified by `https://developer.android.com/reference/java/util/Collection#add(E)`) <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the class of the specified element prevents it from being added to this list |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if some property of this element prevents it from being added to this list |
| `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified element is null and this list does not permit null elements |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the `add` operation is not supported by this list |

### addAll

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean addAll (int index, 
                Collection<? extends E> c)
```

Inserts all of the elements in the specified collection into this list at the specified position (optional operation). 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 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.)

<br />

##### Implementation Requirements:

- This implementation gets an iterator over the specified collection and iterates over it, inserting the elements obtained from the iterator into this list at the appropriate position, one at a time, using `add(int, E)`. Many implementations will override this method for efficiency.

  Note that this implementation throws an `UnsupportedOperationException` unless `https://developer.android.com/reference/java/util/AbstractList#add(int,%20E)` is overridden.

| Parameters ||
|---|---|
| `index` | `int`: index at which to insert the first element from the specified collection <br /> |
| `c` | `Collection`: collection containing elements to be added to this list <br /> |

| Returns ||
|---|---|
| `boolean` | `true` if this list changed as a result of the call <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` |   |

### clear

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void clear ()
```

Removes all of the elements from this list (optional operation). The list will be empty after this call returns.

<br />

##### Implementation Requirements:

- This implementation calls `removeRange(0, size())`.

  Note that this implementation throws an `UnsupportedOperationException` unless `remove(int index)` or `removeRange(int fromIndex, int toIndex)` is overridden.

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the `clear` operation is not supported by this list |

### equals

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean equals (Object o)
```

Compares the specified object with this list for equality. Returns `true` if and only if the specified object is also a list, both lists have the same size, and all corresponding pairs of elements in the two lists are *equal*. (Two elements `e1` and `e2` are *equal* if `(e1==null ? e2==null : e1.equals(e2))`.) In other words, two lists are defined to be equal if they contain the same elements in the same order.

<br />

##### Implementation Requirements:

- This implementation first checks if the specified object is this list. If so, it returns `true`; if not, it checks if the specified object is a list. If not, it returns `false`; if so, it iterates over both lists, comparing corresponding pairs of elements. If any comparison returns `false`, this method returns `false`. If either iterator runs out of elements before the other it returns `false` (as the lists are of unequal length); otherwise it returns `true` when the iterations complete.

| Parameters ||
|---|---|
| `o` | `Object`: the object to be compared for equality with this list <br /> |

| Returns ||
|---|---|
| `boolean` | `true` if the specified object is equal to this list <br /> |

### get

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract E get (int index)
```

Returns the element at the specified position in this list.

<br />

| Parameters ||
|---|---|
| `index` | `int`: index of the element to return <br /> |

| Returns ||
|---|---|
| `E` | the element at the specified position in this list <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` |   |

### hashCode

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public int hashCode ()
```

Returns the hash code value for this list.

<br />

##### Implementation Requirements:

- This implementation uses exactly the code that is used to define the list hash function in the documentation for the `https://developer.android.com/reference/java/util/List#hashCode()` method.

| Returns ||
|---|---|
| `int` | the hash code value for this list <br /> |

### indexOf

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public 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. More formally, returns the lowest index `i` such that `Objects.equals(o, get(i))`, or -1 if there is no such index.

<br />

##### Implementation Requirements:

- This implementation first gets a list iterator (with `listIterator()`). Then, it iterates over the list until the specified element is found or the end of the list is reached.

| Parameters ||
|---|---|
| `o` | `Object`: element to search for <br /> |

| Returns ||
|---|---|
| `int` | the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### iterator

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public Iterator<E> iterator ()
```

Returns an iterator over the elements in this list in proper sequence.

<br />

##### Implementation Requirements:

- This implementation returns a straightforward implementation of the iterator interface, relying on the backing list's `size()`, `get(int)`, and `remove(int)` methods.

  Note that the iterator returned by this method will throw an `https://developer.android.com/reference/java/lang/UnsupportedOperationException` in response to its `remove` method unless the list's `remove(int)` method is overridden.

  This implementation can be made to throw runtime exceptions in the face of concurrent modification, as described in the specification for the (protected) `https://developer.android.com/reference/java/util/AbstractList#modCount` field.

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/Iterator<E>` | an iterator over the elements in this list in proper sequence <br /> |

### lastIndexOf

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public 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. More formally, returns the highest index `i` such that `Objects.equals(o, get(i))`, or -1 if there is no such index.

<br />

##### Implementation Requirements:

- This implementation first gets a list iterator that points to the end of the list (with `listIterator(size())`). Then, it iterates backwards over the list until the specified element is found, or the beginning of the list is reached.

| Parameters ||
|---|---|
| `o` | `Object`: element to search for <br /> |

| Returns ||
|---|---|
| `int` | the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### listIterator

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public ListIterator<E> listIterator (int index)
```

Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. The specified index indicates the first element that would be returned by an initial call to `https://developer.android.com/reference/java/util/ListIterator#next()`. An initial call to `https://developer.android.com/reference/java/util/ListIterator#previous()` would return the element with the specified index minus one.

<br />

##### Implementation Requirements:

- This implementation returns a straightforward implementation of the `ListIterator` interface that extends the implementation of the `Iterator` interface returned by the `iterator()` method. The `ListIterator` implementation relies on the backing list's `get(int)`, `set(int, E)`, `add(int, E)` and `remove(int)` methods.

  Note that the list iterator returned by this implementation will throw an `https://developer.android.com/reference/java/lang/UnsupportedOperationException` in response to its `remove`, `set` and `add` methods unless the list's `remove(int)`, `set(int, E)`, and `add(int, E)` methods are overridden.

  This implementation can be made to throw runtime exceptions in the face of concurrent modification, as described in the specification for the (protected) `https://developer.android.com/reference/java/util/AbstractList#modCount` field.

| Parameters ||
|---|---|
| `index` | `int`: index of the first element to be returned from the list iterator (by a call to `https://developer.android.com/reference/java/util/ListIterator#next()`) <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/ListIterator<E>` | a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` |   |

### listIterator

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public ListIterator<E> listIterator ()
```

Returns a list iterator over the elements in this list (in proper sequence).

<br />

##### Implementation Requirements:

- This implementation returns `listIterator(0)`.

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/ListIterator<E>` | a list iterator over the elements in this list (in proper sequence) <br /> |

**See also:**

- `https://developer.android.com/reference/java/util/AbstractList#listIterator(int)`

### remove

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public E remove (int index)
```

Removes the element at the specified position in this list (optional operation). Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.

<br />

##### Implementation Requirements:

- This implementation always throws an `UnsupportedOperationException`.

| Parameters ||
|---|---|
| `index` | `int`: the index of the element to be removed <br /> |

| Returns ||
|---|---|
| `E` | the element previously at the specified position <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` |   |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` |   |

### set

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public E set (int index, 
                E element)
```

Replaces the element at the specified position in this list with the specified element (optional operation).

<br />

##### Implementation Requirements:

- This implementation always throws an `UnsupportedOperationException`.

| Parameters ||
|---|---|
| `index` | `int`: index of the element to replace <br /> |
| `element` | `E`: element to be stored at the specified position <br /> |

| Returns ||
|---|---|
| `E` | the element previously at the specified position <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` |   |

### subList

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public List<E> subList (int fromIndex, 
                int toIndex)
```

Returns a view of the portion of this list between the specified `fromIndex`, inclusive, and `toIndex`, exclusive. (If `fromIndex` and `toIndex` are equal, the returned list is empty.) The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. The returned list supports all of the optional list operations supported by this list.

This method eliminates the need for explicit range operations (of the sort that commonly exist for arrays). Any operation that expects a list can be used as a range operation by passing a subList view instead of a whole list. For example, the following idiom removes a range of elements from a list:

    list.subList(from, to).clear();

Similar idioms may be constructed for `indexOf` and `lastIndexOf`, and all of the algorithms in the `Collections` class can be applied to a subList.

The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is *structurally modified* in any way other than via the returned list. (Structural modifications are those that change the size of this list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.)

<br />

##### Implementation Requirements:

- This implementation returns a list that subclasses `AbstractList`. The subclass stores, in private fields, the size of the subList (which can change over its lifetime), and the expected `modCount` value of the backing list. There are two variants of the subclass, one of which implements `RandomAccess`. If this list implements `RandomAccess` the returned list will be an instance of the subclass that implements `RandomAccess`.

  The subclass's `set(int, E)`, `get(int)`, `add(int, E)`, `remove(int)`, `addAll(int, Collection)` and `removeRange(int, int)` methods all delegate to the corresponding methods on the backing abstract list, after bounds-checking the index and adjusting for the offset. The `addAll(Collection c)` method merely returns `addAll(size, c)`.

  The `listIterator(int)` method returns a "wrapper object" over a list iterator on the backing list, which is created with the corresponding method on the backing list. The `iterator` method merely returns `listIterator()`, and the `size` method merely returns the subclass's `size` field.

  All methods first check to see if the actual `modCount` of the backing list is equal to its expected value, and throw a `ConcurrentModificationException` if it is not.

| Parameters ||
|---|---|
| `fromIndex` | `int`: low endpoint (inclusive) of the subList <br /> |
| `toIndex` | `int`: high endpoint (exclusive) of the subList <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/List<E>` | a view of the specified range within this list <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the endpoint indices are out of order `(fromIndex > toIndex)` |
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` | if an endpoint index value is out of range `(fromIndex < 0 || toIndex > size)` |

## Protected methods

### removeRange

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
protected void removeRange (int fromIndex, 
                int toIndex)
```

Removes from this list all of the elements whose index is between `fromIndex`, inclusive, and `toIndex`, exclusive. Shifts any succeeding elements to the left (reduces their index). This call shortens the list by `(toIndex - fromIndex)` elements. (If `toIndex==fromIndex`, this operation has no effect.)

This method is called by the `clear` operation on this list and its subLists. Overriding this method to take advantage of the internals of the list implementation can *substantially* improve the performance of the `clear` operation on this list and its subLists.

<br />

##### Implementation Requirements:

- This implementation gets a list iterator positioned before `fromIndex`, and repeatedly calls `ListIterator.next` followed by `ListIterator.remove` until the entire range has been removed. **Note: if `ListIterator.remove` requires linear time, this implementation requires quadratic time.**

| Parameters ||
|---|---|
| `fromIndex` | `int`: index of first element to be removed <br /> |
| `toIndex` | `int`: index after last element to be removed <br /> |