java 8 basic code

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


//sum 
//count
//acending naturalOrder
//decending order 
//even, odd 
//min, max
//find dublicate , revove dublicate
//Convert List to Map, to set, to list, to new collections
//Join strings
//find first, or 1st limit(3), 1st skip(3), 2nd element, highest 2nd,
//partition even & odd
//SummingInt
//avg 
//Group by string length
//count the dublicate 
//Flatten list of lists -> flatMap
//

class Codechef
{
    public static void main(String[] args) throws java.lang.Exception
    {
        System.out.print("Even number: ");
        List < Integer > list = Arrays.asList(7, 5, 3, 2, 3, 4, 5, 6, 7, 8);
        list.stream().filter(n -> n % 2 == 0).forEach(n -> System.out.print(n + " "));
        long Count = list.stream().filter(n -> n % 2 == 0).count();
        System.out.println("Count: " + Count);
        System.out.print("Odd number: ");
        list.stream().filter(n -> n % 2 != 0).forEach(n -> System.out.print(n + " "));
        long count = list.stream().filter(n -> n % 2 != 0).distinct().count();
        System.out.println("Count: " + count);

        System.out.print("Sum: ");
        int sum = list.stream().mapToInt(Integer::intValue).sum();
        System.out.println(sum);

        int max = list.stream().min(Comparator.naturalOrder()).get();
        System.out.println("MAx: " + max);
        System.out.print("rev Sorted list: ");
        list.stream().sorted(Collections.reverseOrder()).distinct().forEach(n -> System.out.print(n + " "));
        System.out.println();
        System.out.print("Dublicate number: ");
        Set < Integer > set = new HashSet < > ();
        list.stream().filter(n -> !set.add(n)).forEach(n -> System.out.print(n + " "));
        System.out.println();
        System.out.print("First number: ");
        list.stream().findFirst().ifPresent(System.out::println);

        int second = list.stream().sorted((a, b) -> b - a).skip(1).findFirst().get();
        System.out.println("Second last number: " + second);

        System.out.print("partition by Even and odd: ");
        Map < Boolean, List < Integer >> map = list.stream().collect(Collectors.partitioningBy(n -> n % 2 == 0));
        System.out.println(map);

        List < String > list3 = Arrays.asList("raj", "sai", "yogesh", "sonar");
        System.out.print("Group by length: ");
        Map < Integer, List < String >> map4 = list3.stream().collect(Collectors.groupingBy(String::length));
        System.out.println(map4);




    }
}