# int cannot be dereferenced
# return year.compareTo(b.year);
A static inner class can NOT be instantiated, through an instance of outer class.
Non static inner class cannot access, without having an instance of the outer class.
/**
* Closes the stream and releases any system resources associated with
* it. Once the stream has been closed, further read(), ready(),
* mark(), reset(), or skip() invocations will throw an IOException.
* Closing a previously closed stream has no effect.
*
* @exception IOException If an I/O error occurs
*/
abstract public void close() throws IOException;