Data Structures and Java collections

List interface, repeatable, ordered. List has ArrayList, because is the array structure, is suitable for the data query, LinkedList, because is the chain list structure, is suitable for uses in the deletion operation. If the array of additions and deletions, need to follow the elements are moving forward or backward, if the first element to make additions and deletions, the following elements move is very large, inefficient. Linked list If you do a query, you need to start from the first element to the last, if the query element in the last, the query volume is also very high, inefficient.

Set interface, non-repeatable, unordered. TreeSet is a tree data structure, is ordered, so TreeSet solves the problem of set can not be sorted. The data structure of hashset is a hash value data structure, so it is unique. Linkedhashset.

Map interface, Hashtable, null not allowed for synchronization

HashMap, out of sync, allows the key and value to be null.

TreeMap, not synchronized, sorted by key, NULL not allowed

Data Structures and Java collections