How to storing Java Object In HashSet

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class HashSetOfObject {
    public static void main(String[] args) {
       
        Set<User> hs = new HashSet<User>();

        hs.add(new User("shivam",1213));
        hs.add(new User("yogesh",8383));
        hs.add(new User("ashwani", 8287));
       
        Iterator<User> itr =hs.iterator();
        while (itr.hasNext()) {
            User user = (User) itr.next();
            System.out.println("userName ="+user.getName()+" userId = "+user.getUserId());
        }
       
       
    }
}

class User{
       
    private String name;
    private int userId;
   
    public User(String name, int userId) {
        super();
        this.name = name;
        this.userId = userId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }
    
}



Output:

userName =ashwani userId = 8287

userName =shivam userId = 1213

userName =yogesh userId = 8383

How to replace element of vector

 We can replace any specific index element by other element using set(int index,element) method.


import java.util.Vector;

public class ReplaceElement {
   
 public static void main(String[] args) {
       
         Vector<String> vector = new Vector<String>();
         //add element in vector
         vector.add("cricket");
         vector.add("hockey");
         vector.add("football");
         vector.add("tennish");
       
         // print vector
         System.out.println("Before replace Vector is = "+vector);
       
         /*
          * Replaces the element at the specified
          * position in this Vector with the
          *  specified element.
          */
         vector.set(1,"Apple");
       
         System.out.println("After Replace element vector is = "+vector);
               
    }

}


Output:

Before replace Vector is = [cricket, hockey, football, tennish]

After Replace element vector is = [cricket, Apple, football, tennish]
 

How to count number of element in vector

Size() Method return number of element in the vector.

import java.util.Vector;

public class CountElement {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector is = "+vector);
      
            /*
             * Returns the number of components in this vector.
             */
        System.out.println("size = "+vector.size());
    }

}

Output:

Vector is = [cricket, hockey, football, tennish]

size = 4
 

How to shuffle elements in Vector

import java.util.Collections;
import java.util.Vector;

public class Shuffle {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
               
        /*
         * Randomly permutes the specified list using a
         *  default source of randomness.
         */
        Collections.shuffle(vector);
      
        System.out.println("Vector after first Shuffle = "+vector);
      
        Collections.shuffle(vector);
      
        System.out.println("Vector after second Shuffle = "+vector);
      
    }
}
   
Output:
Vector = [cricket, hockey, football, tennish]

Vector after first Shuffle = [tennish, cricket, football, hockey]

Vector after second Shuffle = [cricket, hockey, tennish, football]

How to get sub list from Vector

we can use sublist(fromindex,toindex) for get sublist from a vector.

import java.util.List;
import java.util.Vector;

public class GetSubList {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
        vector.add("java");
      
        // print vector
        System.out.println("Vector = "+vector);
               
        /*
         * Returns a view of the portion of this
         *  List between fromIndex, inclusive, and
         *  toIndex, exclusive. (If  fromIndex and toIndex are equal,
         *  the returned List is empty.) T
         */
      
     List<String> list = vector.subList(1,3);
    
     System.out.println("list is ="+list);
      
    }

}

Output:

Vector = [cricket, hockey, football, tennish, java]

list is =[hockey, football]

How to remove all element from vector

We can remove all element of vector using clear() method . clear() removes all element from the list and return empty list.


import java.util.Vector;

public class RemoveAll {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector is = "+vector);
      
        /*
         * Removes all of the elements from this
         * Vector. The Vector will be empty after
         *  this call returns (unless it throws an
         *   exception).
         */
        vector.clear();
      
        System.out.println("Vector After Clear is = "+vector);
               
    }

}


Output:

Vector is = [cricket, hockey, football, tennish]

Vector After Clear is = []

How to swap elements of vector

import java.util.Collections;
import java.util.Vector;

public class SwapElement {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Before swap Vector = "+vector);
      
        /*
         * Swaps the elements at the specified positions
         * in the specified list. (If the specified
         * positions are equal, invoking this method
         * leaves the list unchanged.)
         */
      
        Collections.swap(vector, 1, 3);
      
        System.out.println("After swap vector = "+vector);
               
            }   
   
}

Output:

Before swap Vector = [cricket, hockey, football, tennish]

After swap vector = [cricket, tennish, football, hockey]

Reverse order of all elements of Vector

import java.util.Collections;
import java.util.Vector;

public class ReverseAllelement {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Before reverse Vector = "+vector);
      
        /*
         * Reverses the order of the elements in the
         * specified list. This method runs in linear time.
         */
        Collections.reverse(vector);
      
      System.out.println("After reverse Vector = "+vector);
               
    }
}


Output:

Before reverse Vector = [cricket, hockey, football, tennish]

After reverse Vector = [tennish, football, hockey, cricket]

How To Shallow Copy Or Clone a Vector

import java.util.Vector;

public class CloneOfVector {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
   
        /*
         * Returns a clone of this vector. The copy will
         * contain a reference to a clone of the internal
         *  data array, not a reference to the original internal
         *  data array of this Vector object.
         */
      
        Vector<String> myvector = (Vector<String>) vector.clone();
      
        for (String str : myvector) {

        System.out.println("element is = "+str);
   
         }
      
    }

}