How to find the count of employees in each department using java 8 streams and collection | interview questions MAANG

/**

 * 

 */

package com.learning.stockmarket;

import java.nio.charset.Charset;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Random;

import java.util.stream.Collectors;

/**

 * @author vishnu prasad blog

 *

 */

public class MainClass {

/**

* @param args

*/

public static void main(String[] args) {

List<Employee> empList = addEmployee();

Map<Integer, Long> result = empList.stream().collect(Collectors.groupingBy(Employee:: getDeptId, Collectors.counting()));

System.out.println(result);

}

private static List<Employee> addEmployee() {

List<Employee> list = new ArrayList<>();

int id = 1;

for (int i = 0; i < 100; i++) {

byte[] array = new byte[7]; 

    new Random().nextBytes(array);

    String name = new String(array, Charset.forName("UTF-8"));

    

    int dept = new Random().nextInt(6);

Employee employee = new Employee(id, name, dept);

id = id++;

list.add(employee);

}

return list;

}

}

Employee

/**

 * 

 */

package com.learning.stockmarket;

/**

 * @author vishnu prasad blog

 * Kozhikode

 */

public class Employee {

private int id;

private String name;

private int deptId;

public Employee(int id, String name, int deptId) {

this.id = id;

this.name = name;

this.deptId = deptId;

}

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 int getDeptId() {

return deptId;

}

public void setDeptId(int deptId) {

this.deptId = deptId;

}

}