看不懂HashMap内部的Spliterator不要紧，来看这个简化版本

package design.demo;

import java.util.function.Consumer;

/**
 * @author:ace
 * @date:2020-01-07
 */
public class MySpliterator<T> {

    T[] table;
    int index;
    int fence;

    public MySpliterator(T[] table,int origin,int fence){
        this.table = table;
        this.index = origin;
        this.fence = fence;
    }

    private int getFence(){
        if(fence < 0){
            fence = table.length;
        }
        return fence;
    }
    public MySpliterator<T> trySplit(){
        int hi = getFence();
        int lo = index;
        int mid = (lo + hi) >>> 1;
        if(lo >= mid){
            return null;
        }
        return new MySpliterator<>(table,lo,index=mid);
    }

    public void forEach(Consumer<? super T> action){
        int i,hi;
        if((hi=fence) < 0){
            hi = fence = table.length;
        }
        if(table.length>=hi && (i=index)>=0 && (i< (index = hi)) ){
            do{
                System.out.printf("current index : " + index + " | ");
                action.accept(table[i++]);
            }while(i<hi);
        }
    }


    public static void main(String[] args) {
        String[] strings = new String[16];
        for (int i = 0; i < 16; i++) {
            strings[i] = "string" + i;
        }
        MySpliterator<String> spliterator = new MySpliterator<>(strings,0,-1);

        int index = 1;
        do{
            new Thread(new MyRunnable(spliterator,"thread"+ index++)).start();

        }while((spliterator = spliterator.trySplit())!=null);
    }

    static class MyRunnable implements Runnable{
        MySpliterator<String> spliterator;
        String name;
        public MyRunnable(MySpliterator<String> spliterator,String name){
            this.spliterator = spliterator;
            this.name = name;
        }
        @Override
        public void run() {
            spliterator.forEach(item->{
                System.out.println(name + " : " + item);
            });
        }
    }
}