Sorting an ArrayList(POJO) Using Comparator

Sorting an ArrayList that contains pojo class:

 Please go through the below example.

 First create a new java class and named as Employee.

package com.sana.collections;

public class Employee {
   
    int id;
    String firstName;
    String lastName;

    public Employee(int id, String firstName, String lastName) {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return "Employee{" + "id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + '}';

   // return firstName ;
    }
}

Actual Class for Testing:

Create a new java class named as SortListTest:

package com.sana.collections;

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

class MyComparator implements Comparator<Employee> {

    public int compare(Employee emp1, Employee emp2) {
        // comparing Firstname from both objects @Sorting based on First Name
        return emp1.getFirstName().compareTo(emp2.getFirstName());
    }
}

public class SortListTest {

    public static void main(String[] args) {
        Employee emp1 = new Employee(1, "SHEKAR", "SANA");
        Employee emp2 = new Employee(2, "CHIRU", "ALLEM");
        Employee emp3 = new Employee(3, "CHANDRA", "SHEKAR");
        Employee emp4 = new Employee(4, "Test", "Test");
        Employee emp5 = new Employee(4, "Mahesh", "Burugu");

        List<Employee> employeeList = new ArrayList<Employee>();
        employeeList.add(emp1);
        employeeList.add(emp2);
        employeeList.add(emp3);
        employeeList.add(emp4);
        employeeList.add(emp5);

        Collections.sort(employeeList, new MyComparator());
        for (Employee e : employeeList) {

            System.out.println(e);
        }

    }
}
 

OUTPUT:

Employee{id=3, firstName=CHANDRA, lastName=SHEKAR}
Employee{id=2, firstName=CHIRU, lastName=ALLEM}
Employee{id=4, firstName=Mahesh, lastName=Burugu}
Employee{id=1, firstName=SHEKAR, lastName=SANA}
Employee{id=4, firstName=Test, lastName=Test}

  BY

SANA