Java collections of commonly used features outlined
1 Collection separate collection
List 1.1 (ordered repeatable)
ArrayList : the underlying array, fast queries, additions and deletions slow, thread-safe, efficient, index, repeatable
Vector : is the old version of the ArrayList, the only difference is that Vector is thread-safe
The LinkedList : bottom list (deque), query slow, fast deletions, features list includes
1.2 Set Interface (unordered unique)
HashSet : based on a hash table structure, the only disorder
. A storage disorder because hashCode hash value stored in the index table about the object, hashCode is relatively random, so the disorder;
. B unique, deduplication equals and hashCode method relies on;
c. You can store null, null but can not be repeated.
TreeSet : based on the binary tree structure, the only element, comparable sortable
. A de-duplication, relies on the storage characteristics of the binary tree;
. B taken depends on the characteristics of ordering binary tree;
C. natural ordering and sorting comparator.
LinkedHashSet : linked lists and hash tables, based on the only orderly
. A orderly list to ensure orderly;
b. The only hash table guaranteed to be unique.
Double row set 2 Map
HashMap 2.1 : disorderly, Unique, threads are not synchronized, non-security
LinkedHashMap 2.2 : orderly, threads are not synchronized, non-security
The HashTable 2.3 : disorderly, thread synchronization, security
TreeMap 2.4 : orderly, threads are not synchronized, non-security
