Code

import java.io.*;
import java.util.*;

@SuppressWarnings("unused")
class Student {
	int roll_no, year, sem, age;
	String name;
	float fees;
	String branch;
	static String clg;

	public Student(int roll_no, String name, float fees, String branch, int year, int sem, int age){
		this.roll_no = roll_no;
		this.name = name;
		this.fees = fees;
		this.branch = branch;
		this.year = year;
		this.sem = sem;
		this.age = age;
		clg = "PU";
	}
	@Override
	public String toString() {
		return roll_no + " " + name + " " + fees + " " + branch + " " + year + sem + " " + age + " " + clg + "\n";
	}
}

class AgeComparator implements Comparator<Object> {
	public int compare(Object o1, Object o2) {
		Student s1 = (Student)o1;
		Student s2 = (Student)o2;
		if (s1.age == s2.age) return 0;
		else if (s1.age > s2.age) return 1;
		else return -1;
	}
}

class NameComparator implements Comparator<Object> {
	public int compare(Object o1, Object o2) {
		Student s1 = (Student)o1;
		Student s2 = (Student)o2;
		return s1.name.compareTo(s2.name);
	}
}

class FeesComparator implements Comparator<Object> {
	public int compare(Object o1, Object o2) {
		Student s1 = (Student)o1;
		Student s2 = (Student)o2;
		if (s1.fees == s2.fees) return 0;
		else if (s1.fees > s2.fees) return 1;
		else return -1;
	}
}

public class Temp1 {
	public static void main(String args[]) {
		ArrayList<Student> s1 = new ArrayList<Student>();
		s1.add(new Student(1, "Shiva", 10000.00f, "cse", 1, 1, 18));
		s1.add(new Student(2, "Venky", 15000.00f, "ise", 1, 2, 20));
		s1.add(new Student(3, "Jesus", 17000.00f, "ece", 1, 1, 19));
		s1.add(new Student(3, "Alla", 12000.00f, "eee", 1, 1, 19));
		s1.add(new Student(3, "Budha", 11000.00f, "mech", 1, 1, 21));
		
		System.out.println("Sorting by Name");
		System.out.println("---------------");
		Collections.sort(s1, new NameComparator());
		Iterator<Student> itr = s1.iterator();
		while(itr.hasNext()) {
			Student st = (Student)itr.next();
			System.out.println(st.toString());
		}
		
		System.out.println("Sorting by Age");
		System.out.println("---------------");
		Collections.sort(s1, new AgeComparator());
		Iterator<Student> itr1 = s1.iterator();
		while(itr1.hasNext()) {
			Student st = (Student)itr1.next();
			System.out.println(st.toString());
		}
		
		System.out.println("Sorting by Fees");
		System.out.println("---------------");
		Collections.sort(s1, new FeesComparator());
		Iterator<Student> itr2 = s1.iterator();
		while(itr2.hasNext()) {
			Student st = (Student)itr2.next();
			System.out.println(st.toString());
		}
	}
}