StreamInterviewJavaTechies.java

package InterviewProblems;

import java.util.*;
import java.util.stream.Collectors;


public class StreamInterviewJavaTechies {
    static List<Employee> employeeList = new ArrayList<Employee>();
    public static void main(String[] args) {
        employeeList.add(new Employee(111, "Jiya Brein", 32, "Female", "HR", 2011, 25000.0));
        employeeList.add(new Employee(122, "Paul Niksui", 25, "Male", "Sales And Marketing", 2015, 13500.0));
        employeeList.add(new Employee(133, "Martin Theron", 29, "Male", "Infrastructure", 2012, 18000.0));
        employeeList.add(new Employee(144, "Murali Gowda", 28, "Male", "Product Development", 2014, 32500.0));
        employeeList.add(new Employee(155, "Nima Roy", 27, "Female", "HR", 2013, 22700.0));
        employeeList.add(new Employee(166, "Iqbal Hussain", 43, "Male", "Security And Transport", 2016, 10500.0));
        employeeList.add(new Employee(177, "Manu Sharma", 35, "Male", "Account And Finance", 2010, 27000.0));
        employeeList.add(new Employee(188, "Wang Liu", 31, "Male", "Product Development", 2015, 34500.0));
        employeeList.add(new Employee(199, "Amelia Zoe", 24, "Female", "Sales And Marketing", 2016, 11500.0));
        employeeList.add(new Employee(200, "Jaden Dough", 38, "Male", "Security And Transport", 2015, 11000.5));
        employeeList.add(new Employee(211, "Jasna Kaur", 27, "Female", "Infrastructure", 2014, 15700.0));
        employeeList.add(new Employee(222, "Nitin Joshi", 25, "Male", "Product Development", 2016, 28200.0));
        employeeList.add(new Employee(233, "Jyothi Reddy", 27, "Female", "Account And Finance", 2013, 21300.0));
        employeeList.add(new Employee(244, "Nicolus Den", 24, "Male", "Sales And Marketing", 2017, 10700.5));
        employeeList.add(new Employee(255, "Ali Baig", 23, "Male", "Infrastructure", 2018, 12700.0));
        employeeList.add(new Employee(266, "Sanvi Pandey", 26, "Female", "Product Development", 2015, 28900.0));
        employeeList.add(new Employee(277, "Anuj Chettiar", 31, "Male", "Product Development", 2012, 35700.0));

        //find the total names starts with N
        //method0();
        System.out.println("\n");

        //find the total number of male and female employee
        //method1();
        System.out.println("\n");

        //method2();
        System.out.println("\n");

        //method3();
        System.out.println("\n");

        //method4();
        System.out.println("\n");

        //method5();
        System.out.println("\n");

        method00();
        System.out.println("\n");
    }

    public static void method0() {
        System.out.println("Query 2 : Print the name of all starts with J in the organization?");
        employeeList.stream().filter(x->x.getName().startsWith("J")).distinct().forEach(System.out::println);
    }
    public static void method00() {
        System.out.println("Query 5 : Get the names,age of all employees in ascending order");
//        Optional<Employee> highestPaidEmployeeWrapper =
//                employeeList.stream().collect(Collectors.maxBy(Comparator.comparingInt(Employee::getAge)));
        Map<String, Long> noOfNameAgeEmployees = employeeList.stream()
                .collect(Collectors.groupingBy(Employee::getGender, Collectors.counting()));
        System.out.println(noOfNameAgeEmployees);
    }

    public static void method1() {
        System.out.println("Query 1 : How many male and female employees are there in the organization?");
        Map<String, Long> noOfMaleAndFemaleEmployees = employeeList.stream()
                .collect(Collectors.groupingBy(Employee::getGender, Collectors.counting()));
        System.out.println(noOfMaleAndFemaleEmployees);
    }
    public static void method2() {
        System.out.println("Query 2 : Print the name of all departments in the organization?");
        employeeList.stream().map(Employee::getDepartment).distinct().forEach(System.out::println);
//        List<String> department = employeeList.stream().map(Employee::getDepartment).distinct().collect(Collectors.toList());
//        System.out.println(department);
    }

    public static void method3() {
        System.out.println("Query 3 : What is the average age of male and female employees?");
        Map<String,Double> averageAgeFemaleAndMale = employeeList.stream()
                .collect(Collectors.groupingBy(Employee::getGender, Collectors.averagingInt(Employee::getAge)));
        System.out.println(averageAgeFemaleAndMale);
    }
    public static void method4() {
        System.out.println("Query 4 : Get the details of highest paid employee in the organization?");
        Optional<Employee> highestPaidEmployeeWrapper =
                employeeList.stream().collect(Collectors.maxBy(Comparator.comparingDouble(Employee::getSalary)));
        System.out.println(highestPaidEmployeeWrapper.get().name);
    }
    public static void method5() {
        System.out.println("Query 5 : Get the names of all employees who have joined after 2015?");
        employeeList.stream().filter(s-> s.yearOfJoining > 2015).map(Employee::getName).forEach(System.out::println);
    }
}

class Employee{
    int id;
    String name;
    int age;
    String gender;
    String department;
    int yearOfJoining;
    double salary;

    public Employee(int id, String name, int age, String gender, String department, int yearOfJoining, double salary) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.gender = gender;
        this.department = department;
        this.yearOfJoining = yearOfJoining;
        this.salary = salary;
    }

    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 getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getYearOfJoining() {
        return yearOfJoining;
    }

    public void setYearOfJoining(int yearOfJoining) {
        this.yearOfJoining = yearOfJoining;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                ", department='" + department + '\'' +
                ", yearOfJoining=" + yearOfJoining +
                ", salary=" + salary +
                '}';
    }
}