Java Basics - Must Know The Differences

Java Collections :

List :
Ordered
Contain duplicates

Vector :
Growable array
Synchronized
Multi thread
Default size to 10

Set :
Unordered
No duplicates 

Hashtable :
Key-value
Synchronized
No NULLS
Ordered
Use enumerator

Arraylist :
Heterogeneous
Unsynchronized
Allow NULLS
Uses array structure to store
No default size

Map :
Interface
Associate key with Value

Hashmap :
No order
Unsynchronized
Allow NULLS
Use Iterator
Default size is 8

LinkedList :
Faster to insert/delete in between.