The array immediately following the end of the collection is set to (i.e., the array has more elements than the list), the element in If the list fits in the specified array with room to spare Otherwise, a new array isĪllocated with the runtime type of the specified array and the size of Sequence (from first to last element) the runtime type of the returnedĪrray is that of the specified array. Returns an array containing all of the elements in this list in proper Therefore, it would be wrong to write a program that depended on thisĮxception for its correctness: the fail-fast behavior of iterators Throw ConcurrentModificationException on a best-effort basis. Presence of unsynchronized concurrent modification. Note that the fail-fast behavior of an iterator cannot be guaranteedĪs it is, generally speaking, impossible to make any hard guarantees in the Than risking arbitrary, non-deterministic behavior at an undetermined Thus, in the face ofĬoncurrent modification, the iterator fails quickly and cleanly, rather
If the list is structurally modified at any time after the iterator isĬreated, in any way except through the iterator's ownĬoncurrentModificationException. The iterators returned by this class's iterator and List list = Collections.synchronizedList(new ArrayList(.)) This is best done at creation time, to prevent accidental If no such object exists, the list should be "wrapped" using the Synchronizing on some object that naturally encapsulates the list. Resizes the backing array merely setting the value of an element is notĪ structural modification.) This is typically accomplished by (A structural modification isĪny operation that adds or deletes one or more elements, or explicitly If multiple threads access an ArrayList instance concurrently,Īnd at least one of the threads modifies the list structurally, it Note that this implementation is not synchronized. This may reduce the amount of incremental reallocation. Specified beyond the fact that adding an element has constant amortizedĪn application can increase the capacity of an ArrayList instanceīefore adding a large number of elements using the ensureCapacity
It is alwaysĪt least as large as the list size. The size of the array used to store the elements in the list. To that for the LinkedList implementation.Įach ArrayList instance has a capacity.
That is, adding n elements requires O(n) time. The add operation runs in amortized constant time, Iterator, and listIterator operations run in constant Vector, except that it is unsynchronized.) This class provides methods to manipulate the size of the array that is In addition to implementing the List interface, ImplementsĪll optional list operations, and permits all elements, including Resizable-array implementation of the List interface.
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