abstract class Device class Printer extends devicet abstract class port class SerialPort extends Porti public String toString return“ Printer port”; public Port serial=new SerialPort; class High SpeedPrinter extends Printer( class serialPort extends Printer Port public String to(t return“ HighSpeedPrinter Port”; HighSpeedPrinter printer=new HighSpeedPrinter(; System. out. println(printer: serial);abstract class Device{ abstract class Port{ …… } } class Printer extends Device{ class SerialPort extends Port{ public String toString(){ return “Printer.Port”; } } public Port serial=new SerialPort(); } class HighSpeedPrinter extends Printer{ class SerialPort extends Printer.Port{ public String toString(){ return “HighSpeedPrinter.Port”; } } } HighSpeedPrinter printer=new HighSpeedPrinter(); System.out.println(printer.serial);