Vector:
The Underlying Data Structure is Resizable Array OR Growable Array.
Insertion Order is Preserved.
Duplicate Objects are allowed.
Heterogeneous Objects are allowed.
null Insertion is Possible.
Implements Serializable, Cloneable and RandomAccess interfaces.
Every Method Present Inside Vector is Synchronized and Hence Vector Object is
Thread Safe.
Vector is the Best Choice if Our Frequent Operation is Retrieval.
Worst Choice if Our Frequent Operation is Insertion OR Deletion in the Middle.
Constructors:
1) Vector v = new Vector();
Creates an Empty Vector Object with Default Initial Capacity 10.
Once Vector Reaches its Max Capacity then a New Vector Object will be Created
with
new Capacity = current capacity *2;
Example :
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector();
System.out.println(v.capacity());
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(89);
System.out.println(v.capacity());
System.out.println(v);
}
2)Vector v=new Vector(initial capacity);
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
System.out.println(v.capacity());
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(89);
v.add(null);
v.add(89);
System.out.println(v.capacity());
System.out.println(v);
3) Vector v = new Vector(initial Capacity, int incremental Capacity);
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12,6);
System.out.println(v.capacity());
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(89);
v.add(null);
v.add(89);
System.out.println(v.capacity());
System.out.println(v);
4) Vector v = new Vector(Collection c);
Example :
package list;
import java.util.ArrayList;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
ArrayList al=new ArrayList();
al.add(56);
al.add(78);
al.add(89);
System.out.println(al);
Vector v = new Vector(al);
System.out.println(v.capacity());
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(67);
v.add(89);
v.add(67);
v.add("Santosh");
v.add(null);
v.add(89);
v.add(null);
v.add(89);
System.out.println(v.capacity());
System.out.println(v);
}
Methods of Vector Class:
1) To Add Elements:
add(Object o)Collection
add(int index, Object o)List
addElement(Object o) Vector
Example :
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
v.add(67);
v.addElement(89);
v.add(67);
v.add("Santosh");
v.add(null);
System.out.println(v);
v.add(1, "Bikkad");
System.out.println(v);
2) To Remove Elements:
remove(Object o) Collection
removeElement(Object o)Vector
remove(int index) List
removeElementAt(int index)Vector
clear() Collection
removeAllElements()Vector
Example 1:
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
v.add(67);
v.addElement(89);
v.add(68);
v.add("Santosh");
v.add(null);
System.out.println(v);
v.remove(1);
v.removeElementAt(2);
System.out.println(v);
Example2 :
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
v.add(67);
v.addElement(89);
v.add(68);
v.add("Santosh");
v.add(null);
System.out.println(v);
Integer valueOf = Integer.valueOf(89);
v.remove(valueOf);
Integer valueOf2 = Integer.valueOf(68);
v.removeElement(valueOf2);
System.out.println(v);
Example 3:
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
v.add(67);
v.addElement(89);
v.add(68);
v.add("Santosh");
v.add(null);
System.out.println(v);
// v.clear();
v.removeAllElements();
System.out.println(v);
3) To Retrive Elements:
Object get(int index)List
Object elementAt(int index)Vector
Object firstElement() Vector
Object lastElement()Vector
Example :
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
v.add(67);
v.addElement(89);
v.add(68);
v.add("Santosh");
v.add(null);
System.out.println(v);
System.out.println(v.get(1));
System.out.println(v.elementAt(2));
System.out.println(v.firstElement());
System.out.println(v.lastElement());
System.out.println(v);
4) Some Other Methods:
int size()
int capacity()
Enumeration element()
Example :
package list;
import java.util.Vector;
public class VectorDemo {
public static void main(String[] args) {
Vector v = new Vector(12);
v.add(67);
v.addElement(89);
v.add(68);
v.add("Santosh");
v.add(null);
System.out.println(v.size());
System.out.println(v.capacity());
System.out.println(v);
