Java OCA OCP Practice Question 2572

Question

The following code appears in a file named Book.java. What is the result of compiling the source file? 

1:    public class Book { 
2:       private int pageNumber; 
3:       private class BookReader { 
4:          public int getPage() { 
5:              return pageNumber; 
6:     } } }
  • A. The code compiles successfully, and one bytecode file is generated: Book.class.
  • B. The code compiles successfully, and two bytecode files are generated: Book.class and BookReader.class.
  • C. The code compiles successfully, and two bytecode files are generated: Book.class and Book$BookReader.class.
  • D. A compiler error occurs on line 3.
  • E. A compiler error occurs on line 5.


C.

Note

The code compiles fine.

A member inner class is allowed to be private, and it is allowed to refer to instance variables from the outer class.

Two.class files are generated.

Book.class matches the name of the outer class.

The inner class does not compile to BookReader.class.

That would introduce the possibility of a naming conflict.

Book$BookReader.class is correct because it shows the scope of the class is limited to Book.

You don't need to know that $ is the syntax, but you do need to know the number of classes and that BookReader is not a top-level class.




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