//package jie_shu_xi_tong;import java.util.*;class LibrarySystem{ public static void main(String args[]){ System.out.println("001號借書系統為您服務請選擇您要的服務："+"\n"+ ? ? ? ? ? ? ? ? ? "(1) ? ?按照書名查找"+"\n"+ ? ? ? ? ? ? ? ? ? "(2) ? ?按照圖書序號查找"); } }public class BookData{/*這是問題 ? ? E:\java 筆記和錯誤\yuanwenjian\LibrarySystem.java:15: class BookData is public, should be declared in a file named BookData.java*/public class BookData{ String Bookdata[] = new String[2];//Bookdata代表圖書資料，存儲書本的名稱 public BookData(){ Bookdata[0] = "孫子兵法"; Bookdata[1] = "黃帝內經"; } }public class BookFind extends BookData{/*這是問題 ? ? ?E:\java 筆記和錯誤\yuanwenjian\LibrarySystem.java:23: class BookFind is public, should be declared in a file named BookFind.javapublic class BookFind extends BookData{*/ public BookFind(String BF){ BookData B = new BookData(); for(int i=0;i<B.Bookdata.length;i++){ if(B.Bookdata[i].equale(BF)){/*這是問題E:\java 筆記和錯誤\yuanwenjian\LibrarySystem.java:28: cannot find symbolsymbol ?: method equale(java.lang.String)location: class java.lang.String? ? ? ? ? ? ? ? ? ? ? ? if(B.Bookdata[i].equale(BF)){*/ System.out.println("您要的書"); } } } }