求个java题目 谢谢

求个java题目 谢谢

package edu.abc.test;
这个题目很简单，如果题主要从事程序员工作，得好好努力了
public class Book {
private String title;
private String pageNum;

public void detail() {
System.out.println(this.title + this.pageNum);
}

public String getTitle() {
return title;
}

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

public String getPageNum() {
return pageNum;
}

public void setPageNum(String pageNum) {
this.pageNum = pageNum;
}

}

package edu.abc.test;

import java.util.ArrayList;
import java.util.List;

public class BookTest1{
public static void main(String args[]){
List bookList = new ArrayList();
Book book1 = new Book();
book1.setTitle("java入门");
book1.setPageNum("156");
Book book11 = new Book();
book11.setTitle("java基础");
book11.setPageNum("188");
bookList.add(book1);
bookList.add(book11);
for(Book book:bookList){
book.detail();
}
}
}

package edu.abc.test;

import java.util.HashMap;

public class BookTest2 {
public static void main(String[] args) {
HashMap map = new HashMap();
Book book1 = new Book();
book1.setTitle("java入门");
book1.setPageNum("156");
Book book11 = new Book();
book11.setTitle("java基础");
book11.setPageNum("188");
map.put("100001", book1);
map.put("100002", book11);

Book bookResult =(Book)map.get("100002");
System.out.println(bookResult.getTitle());
}
}