How to Sort Vector Elements in Java

Here we will learn how to sort elements of Vector in descending order with comparator and reverseOrder method of Collections class.

Source Code

package com.beginner.examples;

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

public class SortOfVectorExample {

	
	public static void main(String[] args) {
		
		Vector vector = new Vector();
		//Add elements
		vector.add(5);
		vector.add(6);
		vector.add(3);
		vector.add(1);
		vector.add(7);
		
		System.out.println("unsorted:"+vector);
		/*
		 *  Use the sort() method in the Collections class to sort
		 *  Use a method with one argument,
		 *  The object stored in the vector must implement the Comparable interface
		 *  The Integer type added here already implements the Comparable interface
		 */
		Collections.sort(vector);
		
		System.out.println("After the sorting:"+vector);
		

	}

}

Output:

unsorted:[5, 6, 3, 1, 7]
After the sorting:[1, 3, 5, 6, 7]

2.Custom comparator class)

package com.beginner.examples;
import java.util.Comparator;

public class MyComparator implements Comparator
{

	@Override
	public int compare(Integer o1, Integer o2) {
		
		int result =o2-o1;
		
		return result;
		
	}
	
}

package com.beginner.examples;

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

public class SortOfVectorExample2 {

	/**
	 * Custom comparator
	 */
	public static void main(String[] args) {
		Vector vector = new Vector();
		// Add elements
		vector.add(5);
		vector.add(6);
		vector.add(3);
		vector.add(1);
		vector.add(7);

		System.out.println("unsorted:" + vector);
		/*
		 * When you make a custom comparison, you need to pass in a comparator
		 * Mycomparator is a custom comparator
		 */
		Collections.sort(vector, new MyComparator());

		System.out.println("After the sorting:" + vector);

	}

}

Output:

unsorted:[5, 6, 3, 1, 7]
After the sorting:[7, 6, 5, 3, 1]

References

Imported packages in Java documentation:

How to Sort Vector Elements in Java

In this example we will learn how to sort elements of Java Vector in descending order with comparator and reverseOrder method of Collections class.

Source Code

package com.beginner.examples;

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

public class SortJavaVector {

	public static void main(String[] args) {
		
		//create Vector.
		Vector vector = new Vector();
		
		vector.add(new Integer("54"));
		vector.add(new Integer("689"));
		vector.add(new Integer("13"));
		vector.add(new Integer("369"));
		
		/*
		 To sort a Vector object, use Collection.sort method.
		*/
		Collections.sort(vector);
		
		System.out.println("Vector elements after sorting is ");
		for(int i=0; i<vector.size(); i++)
		      System.out.println(vector.get(i));
	}

}

Output:

Vector elements after sorting is 
13
54
369
689

References

Imported packages in Java documentation: