plz
tell me the use of vector
& how is diff from array

define a variable of type Vector, and call the vector constructor.

Vector myVector = new Vector ();

OR
myVector = new Vector(50);

dynamically increase the size of the vector, bt in case of array the size is fixed.

2] Implement the Enumeration interface which makes traversing the contents of a Vector extremely easy.
ex
for (Enumeration e = myVector.elements(); e.hasMoreElements()
{
String myString = (String) e.nextElement();
System.out.println(myString);
}
3] Arrays in Java are static lists declared to store a certain number of a certain kind of variables.
Vector in java are lists declared to store any number of nay kind of variables.

vector is a synchronized data structure
array is unsynchronized data structure
main difference is synchronized data structure performance is low compare with unsynchronized one.
when ever you feel a block of code is accessed by morethan one thread that time you go for synchronized data structures (i.e is thread safe)