Java 8 : count, max and min operations

Here in this code example we will go through the max, min and count operations which we can use as part of new functionality introduced by Java 8.

count() – Returns the count of elements in the stream.

max() – This method returns the max element of a stream. It returns an Optional. We should do a get() call on that to get the actual object.

min() – This method returns the max element of a stream. It returns an Optional. We should do a get() call on that to get the actual object.

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

class Student {

    private String name;
    private int round;
    private int points;
    
    public Student(String name, int round, int points) {
        super();
        this.name = name;
        this.round = round;
        this.points = points;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getRound() {
        return round;
    }
    public void setRound(int round) {
        this.round = round;
    }
    public int getPoints() {
        return points;
    }
    public void setPoints(int points) {
        this.points = points;
    }
}

public class Java8GroupByExample {
    public static void main(String args[]) {
      
     List<Integer> numList = Java8GroupByExample.getNumbersList();
     Long count = numList.stream().count();
     System.out.println("The count is "+count);
     
     Integer max = numList.stream().max(Comparator.comparing(Integer::valueOf)).get();
     System.out.println("The max is "+max);
     
     Integer min = numList.stream().min(Comparator.comparing(Integer::valueOf)).get();
     System.out.println("The min is "+min);
     
     List<Student> studList = Java8GroupByExample.createStudList();
     
     Comparator<Student> comparator = Comparator.comparing(Student::getPoints);
     Student minStud = studList.stream().min(comparator).get();
     System.out.println("The student with min points is "+minStud.getName());
     
     Student maxStud = studList.stream().max(comparator).get();
     System.out.println("The student with max points is "+maxStud.getName());
      
    }
    
    private static List<Integer> getNumbersList(){
        
        List<Integer> list = new ArrayList<Integer>();
        list.add(5);
        list.add(12);
        list.add(9);
        list.add(15);
        list.add(25);
        list.add(4);
        
        return list;
    }
    
    public static List<Student> createStudList()
    {
        List<Student> studList=new ArrayList<Student>();
    
        Student s1=new Student("Nathan",1,500); 
        Student s2=new Student("Chris",1,1000);  
        Student s3=new Student("David",1,100);
        Student s4=new Student("James",1,300);
        Student s5=new Student("Mike",1,3000);
    
        studList.add(s1);
        studList.add(s2);
        studList.add(s3);
        studList.add(s4);
        studList.add(s5);
    
        return studList;
    }
    
}