Program: How to get max element of a list of user defined objects?

Collections.max() method returns the maximum element of the given collection, according to the natural ordering of its elements. All elements in the collection must implement the Comparable interface. Furthermore, all elements in the collection must be mutually comparable (that is, e1.compareTo(e2) must not throw a ClassCastException for any elements e1 and e2 in the collection). Below example shows how to get max salary from the given list of user defined objects.

package com.java2novice.collections;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class MyMaxUDOComparable {

	public static void main(String a[]){
		
		List<Empl> emps = new ArrayList<Empl>();
		emps.add(new Empl(10, "Raghu", 25000));
		emps.add(new Empl(120, "Krish", 45000));
		emps.add(new Empl(210, "John", 14000));
		emps.add(new Empl(150, "Kishore", 24000));
		Empl maxSal = Collections.max(emps);
		System.out.println("Employee with max salary: "+maxSal);
	}
}

class Empl implements Comparable<Empl>{
	
	private int id;
	private String name;
	private Integer salary;
	
	public Empl(int id, String name, Integer sal){
		this.id = id;
		this.name = name;
		this.salary = sal;
	}
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getSalary() {
		return salary;
	}
	public void setSalary(Integer salary) {
		this.salary = salary;
	}
	@Override
	public int compareTo(Empl emp) {
		
		return this.salary.compareTo(emp.getSalary());
	}
	public String toString(){
		return id+"  "+name+"   "+salary;
	}
}

Employee with max salary: 120  Krish   45000