Sorting Employees by Salary in Reverse Order using Java 8 Streams

Tweet

Question: How can we sort a list of employees by their salary in reverse order using Java 8 streams?

Answer:

1. Create an Employee Class:

   • First, create an Employee class that includes properties like name and salary. This class will represent the structure of your employee objects.

   java
   public class Employee {
       private String name;
       private double salary;
   
       public Employee(String name, double salary) {
           this.name = name;
           this.salary = salary;
       }
   
       // Getters and setters for name and salary (not shown for brevity)
   }

2. Create a List of Employees:

   • Next, create a list of Employee objects to work with. Populate this list with employee data.

   java
   List<Employee> employees = new ArrayList<>();
   employees.add(new Employee("Alice", 60000));
   employees.add(new Employee("Bob", 75000));
   employees.add(new Employee("Charlie", 50000));
   employees.add(new Employee("David", 90000));

3. Sort Employees by Salary in Reverse Order:

   • To sort employees by salary in reverse order, you can use Java 8 streams. Here's the code for this step:

   java
   List<Employee> sortedEmployees = employees.stream()
           .sorted(Comparator.comparing(Employee::getSalary).reversed())
           .collect(Collectors.toList());
   

   • In this code, we use the stream() method to convert the list of employees into a stream.
   • The sorted method is used to perform the sorting.
   • 
     
   • We pass a comparator that compares employees based on their salary in reverse order using Comparator.comparing(Employee::getSalary).reversed().
   • 
     
   • Finally, we collect the sorted employees back into a list using collect(Collectors.toList()).
   • 
     
   • Print the Sorted List:
4. • After sorting, you can print the sorted list to see the results.

   java
   sortedEmployees.forEach(employee -> System.out.println("Name: " + employee.getName() + ", Salary: " + employee.getSalary()));

Example Code:

java
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class EmployeeSortingExample {
    public static void main(String[] args) {
        // Create a list of employees
        List<Employee> employees = new ArrayList<>();
        employees.add(new Employee("Alice", 60000));
        employees.add(new Employee("Bob", 75000));
        employees.add(new Employee("Charlie", 50000));
        employees.add(new Employee("David", 90000));

        // Sort employees by salary in reverse order
        List<Employee> sortedEmployees = employees.stream()
                .sorted(Comparator.comparing(Employee::getSalary).reversed())
                .collect(Collectors.toList());

        // Print the sorted list
        sortedEmployees.forEach(employee -> System.out.println("Name: " + employee.getName() + ", Salary: " + employee.getSalary()));
    }
}

Sample Output:

output
Name: David, Salary: 90000.0
Name: Bob, Salary: 75000.0
Name: Alice, Salary: 60000.0
Name: Charlie, Salary: 50000.0

This code example demonstrates how to sort a list of employees by their salaries in reverse order using Java 8 streams, providing you with a sorted list of employees based on their salary, from highest to lowest.