An array represents a contiguous block of memory where
objects are stored and accessed via a 0-based index value.
Arrays are usually fixed size once they are created.

A java.util.Vector is an implementation of a resizable
array. It has similar functionality as an array but also
gives the advantage of resizability when u try to add
elements to it exceeding its initial size.

The problem is that Vectors are synchronized which is not
necessary for many purposes and this may bring down
performance. Hence the use of ArrayList over Vecotor is
recommended. An ArrayList provides the same functionality of
a Vector, except tat it is not synchronized.

Arrays group values and permit fast access by numeric 
index. Vectors are a variant of arrays that also permit 
fast access by numeric index.

They differ from each other in this way.
vector can grow and shrink dynamically where as array 
cannot.

vectors can be synchronised where as arrays cannot be.

vecotrs are implemented from list interface where as arrays 
are primitive datatypes.

arrays have elements of same datatypes, but vector can have 
elements of any types.