Collection
By Tiationg Kho |
Collection
- A collection in Java is a framework that provides an architecture to store and manipulate a group of objects
| Collection | Ordering | Duplicates | Null Values | Key Characteristics |
|---|
| ArrayList | Ordered (index) | Yes | Yes | Resizable array and good for random access and iterating |
| LinkedList (as queue) | FIFO | Yes | Yes | Doubly-linked list |
| ArrayDeque (as queue) | FIFO | Yes | No | Resizable array |
| ArrayDeque (as stack) | LIFO | Yes | No | Resizable array |
| PriorityQueue | Natural ordering | Yes | No | Elements are ordered by default comparator or provided one |
| TreeSet | Sorted | No | No | Elements are sorted and unique |
| HashSet | Unordered | No | Yes | Hashtable based |
| LinkedHashSet | Insertion order | No | Yes | Hashtable and linked list based |
| TreeMap | Sorted | Keys: No, Values: Yes | Keys: No, Values: Yes | Red-Black tree |
| Hashtable | Unordered | Keys: No, Values: Yes | Keys: No, Values: No | Legacy |
| HashMap | Unordered | Keys: No, Values: Yes | Keys: Once, Values: Yes | Hashtable based (array plus linked list or red-black tree) |
| LinkedHashMap | Insertion order | Keys: No, Values: Yes | Keys: Once, Values: Yes | Hashtable and linked list based |