java.util · java.base · since Java 1.2

List

declaration

public interface List<E> extends SequencedCollection<E>

An ordered, indexed sequence allowing duplicates. The interface to declare against; ArrayList is the default implementation.

List.of(...) has fixed-arity overloads for 0–10 elements plus a varargs form, avoiding an extra array allocation for common literal sizes
addFirst/addLast/getFirst/getLast (SequencedCollection, Java 21) are convenience defaults — on ArrayList only addFirst is an O(n) shift; addLast is amortized O(1) and getFirst/getLast are O(1)

Key methods

`E get(int) / E set(int, E)`	Positional access.
`void add(int, E) / E remove(int)`	Positional insertion/removal (shifts).
`boolean contains(Object)`	Membership via equals() — O(n) unless the implementation says otherwise.
`int indexOf(Object) / lastIndexOf(Object)`	First/last matching position via equals(), or -1.
`boolean addAll(int, Collection<? extends E>)`	Bulk insert at a position.
`void replaceAll(UnaryOperator<E>)`	In-place transform of every element.
`ListIterator<E> listIterator() / listIterator(int)`	Bidirectional cursor supporting set()/add() mid-iteration — richer than Iterator.
`static <E> List<E> of(E...)`	Immutable, null-hostile literal lists.
`static <E> List<E> copyOf(Collection<E>)`	Immutable defensive copy.
`List<E> subList(int from, int to)`	Write-through range VIEW.
`void sort(Comparator<? super E>)`	In-place stable sort (null = natural order).
`List<E> reversed()`	Reversed view (SequencedCollection, Java 21).
`E getFirst() / E getLast()`	Head/tail access, throws if empty (SequencedCollection, Java 21).
`void addFirst(E) / addLast(E)`	Head/tail insertion (SequencedCollection, Java 21).
`boolean equals(Object) / int hashCode()`	Content equality by element order — independent of the concrete implementation.