JUC forkjoin and completable future

ForkJoin Code

package com.cb.demo.example;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

class MyTask extends RecursiveTask<Integer>{

    private static final Integer ADJUST_VALUE=10;

    private int begin;
    private int end;
    private int result;

    public MyTask(int begin,int end){
        this.begin=begin;
        this.end=end;
    }

    @Override
    protected Integer compute() {

        if ((end-begin)<=ADJUST_VALUE){
            for (int i = begin; i <=end ; i++) {
                result=result+i;
            }
        }else{
            int middle=(end+begin)/2;
            MyTask task=new MyTask(begin,middle);
            MyTask task1=new MyTask(middle+1,end);
            task.fork();
            task1.fork();
            result=task.join()+task1.join();
        }

        return result;
    }
}

public class ForkJoinDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
            MyTask myTask=new MyTask(0,100);
        ForkJoinPool threadPool=new ForkJoinPool();

        ForkJoinTask<Integer> forkJoinTask= threadPool.submit(myTask);
        System.out.println(forkJoinTask.get());

        threadPool.shutdown();
    }
}

CompletableFuture Code

package com.cb.demo.example;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class CompletableFutureDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CompletableFuture<Void> completableFuture = CompletableFuture.runAsync(() -> {
            System.out.println(Thread.currentThread().getName() + " No return ");
        });
        completableFuture.get();

        // Asynchronous callback 
        CompletableFuture<String> stringCompletableFuture = CompletableFuture.supplyAsync(() -> {
            System.out.println(Thread.currentThread().getName() + " There is a return ");
            int age=10/0;
            return "2022";
        });

        stringCompletableFuture.whenComplete((t,u)->{
            System.out.println("-------t:"+t);
            System.out.println("-------u:"+u);
        }).exceptionally(f->{
            System.out.println("***excption"+f.getMessage());
            return "404";
        }).get();
    }
}