[OCPJP]繼承與可見度

Given:

public class Book {

    private String read(String bname) {
        return "Read" + bname;
    }
}

public class EBook extends Book {

    public String read(String url) {
        return "View" + url;
    }
}

public class Test {

    public static void main(String[] args) {
        Book b1 = new Book();
        b1.read("Java Programing");
        Book b2 = new EBook();
        b2.read("http://ebook.com/ebook");
    }
}

What is the result?

A.

B. C. The EBook.java file fails to compile.
D. The Test.java file fails to compile.

題解

Test類別會編譯失敗，因為Book物件的read方法是private可見度，第5行和第7行都會編譯失敗。