vector is synchronized . collection object and variable 
slow acess. muntable
array list is never snchronized. collection variable fast 
acess

Vector is synchronized and compare to array list this slow 
access, by defaulst the vector is 10,this is legacy class 
Where as arraylist is unsynchronized and fast random 
access,in arraylist there is no default size automatically 
it is growable once the object is created it will be 
allocated,this is advanced class.