代码如下，使用Collections的max方法

import cn.hutool.core.date.DateUtil;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.List;

/**
 * @author ：Phil Tse
 * @date ：Created in 2021/5/10 17:17
 * @description：测试类
 * @modified By：
 * @version: $
 */
public class Test {
    public static void main(String[] args) {

        List<Date> list = new ArrayList<>();
        list.add(DateUtil.parse("2021-05-11 00:00:00"));
        list.add(DateUtil.parse("2021-05-12 00:00:00"));
        list.add(DateUtil.parse("2021-05-13 00:00:00"));
        list.add(DateUtil.parse("2021-05-14 00:00:00"));
        list.add(DateUtil.parse("2021-05-15 00:00:00"));
        list.add(DateUtil.parse("2021-05-16 00:00:00"));
        TestBean testBean = new TestBean();
        testBean.setTime(list);

        test2(testBean);
    }

    public static void test2(TestBean testBean){
        System.out.println(Collections.max(testBean.getTime()));
    }
}

输出结果如下：

image.png

stream流：

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.List;

/**
 * @author ：Phil Tse
 * @date ：Created in 2021/5/10 17:17
 * @description：
 * @modified By：
 * @version: $
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class TestBean {
//    private Date time;
    private List<TestBeanList> testBeanLists;
}

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

/**
 * @author ：Phil Tse
 * @date ：Created in 2021/5/28 11:43
 * @description：
 * @modified By：
 * @version: $
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class TestBeanList {
    private Date time;
}

import cn.hutool.core.date.DateUtil;

import java.util.*;

/**
 * @author ：Phil Tse
 * @date ：Created in 2021/5/10 17:17
 * @description：测试类
 * @modified By：
 * @version: $
 */
public class Test {
    public static void main(String[] args) {

//        List<Date> list = new ArrayList<>();
//        list.add(DateUtil.parse("2021-05-11 00:00:00"));
//        list.add(DateUtil.parse("2021-05-12 00:00:00"));
//        list.add(DateUtil.parse("2021-05-13 00:00:00"));
//        list.add(DateUtil.parse("2021-05-14 00:00:00"));
//        list.add(DateUtil.parse("2021-05-15 00:00:00"));
//        list.add(DateUtil.parse("2021-05-16 00:00:00"));

        List<TestBeanList> testBeans = new ArrayList<>();
        TestBean testBean = new TestBean();
        testBeans.add(new TestBeanList(DateUtil.parse("2021-05-11 00:00:00")));
        testBeans.add( new TestBeanList(DateUtil.parse("2021-05-12 00:00:00")));
        testBeans.add(new TestBeanList(DateUtil.parse("2021-05-13 00:00:00")));
        testBeans.add( new TestBeanList(DateUtil.parse("2021-05-16 00:00:00")));
        testBean.setTestBeanLists(testBeans);
        test2(testBean);
    }

    public static void test2(TestBean testBeans){
        //Collections.max排序
        Optional<Date> date = //testBeans.getTestBeanLists().stream().sorted(Comparator.comparing(TestBeanList::getTime).reversed()).findFirst().map(TestBeanList::getTime);
        //优化
        Optional<Date> date = testBeans.getTestBeanLists().stream().max(Comparator.comparing(TestBeanList::getTime)).map(TestBeanList::getTime);
        System.out.println(date.get());
    }

}

输出结果：

image.png