need answer like very clearly and ASAP

1-You are required to develop a program (using JAVA) for one of the following situation -Grocery Shop a) Your program should have a super class and two subclasses which the two subclasses are interrelated with the super class. All classes must provide complete methods. Show at least one method in both subclasses which use the same method name. Put that method as abstract method in the super class. b) You also must create a custom(user-defined) Exception class which relevant to your program. c) Create a driver program to receive minimum of 4 different objects. Your driver program should answer several unique questions which covers all classes. Please provide three questions which one of the questions use the abstract method. Use the casting methods in the main program as an alternative in searching process