Compile Java File: CollectionsSortExample4

import java.util.*;
public class CollectionsSortExample4 {
	public static void main (String[] args)
    {
        ArrayList<Student> arr = new ArrayList<Student>();
        arr.add(new Student(101, "Java", "USA"));
        arr.add(new Student(103, "Ruby", "China"));
        arr.add(new Student(102, "Android", "India"));
        System.out.println("Data before sorted-");
        for (int i=0; i<arr.size(); i++)
            System.out.println(arr.get(i));
        //Sorting data according to specified comparator
        Collections.sort(arr, new Sortbyroll());
        System.out.println("Data after sorted by rollno-");
        for (int i=0; i<arr.size(); i++)
            System.out.println(arr.get(i));
    }
}
//Class which represents a student data.
class Student
{
	int rollno;
	String name, address;
	//Constructor
	public Student(int rollno, String name, String address)
	{
		this.rollno = rollno;
		this.name = name;
		this.address = address;
	}
	//Prints student data
	public String toString()
	{
		return this.rollno + " " + this.name + " " + this.address;
	}
}
class Sortbyroll implements Comparator<Student>
{
	//Used for sorting in ascending order of roll number
	public int compare(Student a, Student b)
	{
		return a.rollno - b.rollno;
	}
}

Output

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