以下是一个示例代码，演示了如何按照日期将两个不同的POJO对象合并排序：

import java.time.LocalDate;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

class POJO1 {
    private String name;
    private LocalDate date;

    public POJO1(String name, LocalDate date) {
        this.name = name;
        this.date = date;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public LocalDate getDate() {
        return date;
    }

    public void setDate(LocalDate date) {
        this.date = date;
    }
}

class POJO2 {
    private String title;
    private LocalDate date;

    public POJO2(String title, LocalDate date) {
        this.title = title;
        this.date = date;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public LocalDate getDate() {
        return date;
    }

    public void setDate(LocalDate date) {
        this.date = date;
    }
}

public class Main {
    public static void main(String[] args) {
        // 创建POJO1对象列表
        List list1 = new ArrayList<>();
        list1.add(new POJO1("John", LocalDate.of(2022, 1, 1)));
        list1.add(new POJO1("Alice", LocalDate.of(2022, 2, 1)));
        list1.add(new POJO1("Bob", LocalDate.of(2021, 12, 1)));

        // 创建POJO2对象列表
        List list2 = new ArrayList<>();
        list2.add(new POJO2("Title 1", LocalDate.of(2022, 3, 1)));
        list2.add(new POJO2("Title 2", LocalDate.of(2022, 4, 1)));
        list2.add(new POJO2("Title 3", LocalDate.of(2022, 2, 1)));

        // 合并两个列表
        List