check a json list is sorted or not

item.java

package com.usersapi;

import java.util.Date;

@lombok.Data
public class Item {
    private Date timestamp;
}

StreamTest.java

package com.usersapi;


import com.alibaba.fastjson.JSONArray;

import java.io.InputStream;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class Streamtest {

    public static void main(String[] args) {
        String jsonString = "[{\"timestamp\": \"2021-11-02T00:00:00Z\"}, {\"timestamp\": \"2021-11-02T00:00:00Z\"}, {\"timestamp\": \"2022-01-03T00:00:00Z\"}]";
        List<Item> dateList = JSONArray.parseArray(jsonString, Item.class);
        Boolean isNotSorted = IntStream.range(1, dateList.size())
                .mapToObj(i -> dateList.get(i).getTimestamp().before(dateList.get(i-1).getTimestamp()))
                .anyMatch(o->o);
        if(isNotSorted){
            throw new IllegalStateException("the json list is not sorted by time field");
        }
    }
}