" + title + "

<book.java>
package books;

import java.io.PrintStream;

public class Book {
	private String title;
	private String author;
	private String isbn;
	
	public Book(String title, String author, String isbn) {
		this.title = title;
		this.author = author;
		this.isbn = isbn;
	}
	
	public String getTitle() {
		return title;
	}
	public String getAuthor() {
		return author;
	}
	public String getIsbn() {
		return isbn;
	}

	public void writeAsXml(PrintStream ps) {
		ps.println(" <book>");
		ps.println("  <title>" + title + "</title>");
		ps.println("  <author>" + author + "</author>");
		ps.println("  <isbn>" + isbn + "</isbn>");
		ps.println(" </book>");
	}
}

<booklist>
package books;

import java.io.PrintStream;
import java.util.ArrayList;
import java.util.List;

public class BookList {
	private List<Book> books = new ArrayList<Book>();

	public BookList() {
		// empty
	}
	
	public void addBook(Book book) {
		books.add(book);
	}
	
	public void writeAsXml(PrintStream ps) {
		ps.println("<book-list>");
		for (Book b : books) {
			b.writeAsXml(ps);
		}
		ps.println("</book-list>");
		ps.close();
	}

	public void add(Book b) {
		books.add(b);
	}
}

<booktest>
package test;

import books.Book;
import books.BookList;

public class BooksTest {

	/**
	 * BookListクラスのテストプログラム
	 */
	public static void main(String[] args) {
		BookList bl = new BookList();
		Book b1 = new Book("Java入門", "鈴木　健", "1234-5678-90");
		bl.add(b1);
		Book b2 = new Book("コンピュータ入門", "佐藤　桂子", "1234-8765-43");
		bl.add(b2);
		Book b3 = new Book("OS入門", "田中　和博", "1234-1234-56");
		bl.add(b3);
		bl.writeAsXml(System.out);
	}

}