in java, I need a simple gym management system with these requirements  please help me, please   Requirements Propose and implement an application, that contributes to solving a real-life problem. Your application should include at least the following: 2.1 Classes 3 to 4 classes each one of them should have: A. A number of private and public attributes. The private attributes (variables) will need corresponding set/get methods. B. 2 or more constructors, one of then should take all the class’s data members (attributes) as arguments. C. Some functionality methods that can demonstrate the relationship between different classes. For example, assume that we have a system for a hotel, where a costumer can book a room. Each costumer has an ID (private) and a name. Each room has a number and price. The relationship between the Customer class and the Room class is books as illustrated in the following class diagram: This relationship should be implemented in the Customer side as a method that takes a Room object as an argument, so when a customer books a room, the room object will be stored for example in an ArrayList or a file in case if the customer is allowed to book more than one room. D. Each class should have a printDetails method that will print out to the user the details of an object . E. One Main (Test) class to create objects out of the classes in your application, and to demonstrate the interaction between these objects. 2.2 Objects A. In the Main (Test) class create at least 3 objects out of each class using different constructors. B. After creating the objects, show how could you read or change the values of the private attributes. C. Demonstrate the interaction (relationships) between these created objects. For example, assuming that you have created a customer object (c1) and a room object (r1), you can use the method books to book r1 for c1 as follows: c1.books(r1); D. Make a demo that shows the details to the user for each created object. 2.3 Files and Arrays A. When you create an object in the Test class, read the values of the object variables from the user (e.g., the value of an ID). B. After creating the objects store them temporally in an array (ArraList preferable). Then store them permanently in a file. C. When printing out the detail for an object read them from that file. 2.4 Input Validation A. Apply input validation where needed, for example, in the example given above, the price of a room should not be a negative value, or you can’t have two customers with the same ID.

in java, I need a simple gym management system with these requirements 

please help me, please 

 Requirements
Propose and implement an application, that contributes to solving a real-life problem.
Your application should include at least the following:
2.1 Classes
3 to 4 classes each one of them should have:
A. A number of private and public attributes. The private attributes (variables) will
need corresponding set/get methods.
B. 2 or more constructors, one of then should take all the class’s data members
(attributes) as arguments.
C. Some functionality methods that can demonstrate the relationship between
different classes. For example, assume that we have a system for a hotel, where a
costumer can book a room. Each costumer has an ID (private) and a name. Each
room has a number and price. The relationship between the Customer class and
the Room class is books as illustrated in the following class diagram:
This relationship should be implemented in the Customer side as a method that
takes a Room object as an argument, so when a customer books a room, the room
object will be stored for example in an ArrayList or a file in case if the customer
is allowed to book more than one room.
D. Each class should have a printDetails method that will print out to the user the
details of an object .
E. One Main (Test) class to create objects out of the classes in your application, and
to demonstrate the interaction between these objects.
2.2 Objects
A. In the Main (Test) class create at least 3 objects out of each class using different
constructors.
B. After creating the objects, show how could you read or change the values of the
private attributes.
C. Demonstrate the interaction (relationships) between these created objects. For
example, assuming that you have created a customer object (c1) and a room
object (r1), you can use the method books to book r1 for c1 as follows:
c1.books(r1);
D. Make a demo that shows the details to the user for each created object.
2.3 Files and Arrays
A. When you create an object in the Test class, read the values of the object variables
from the user (e.g., the value of an ID).
B. After creating the objects store them temporally in an array (ArraList preferable).
Then store them permanently in a file.
C. When printing out the detail for an object read them from that file.

2.4 Input Validation
A. Apply input validation where needed, for example, in the example given above, the
price of a room should not be a negative value, or you can’t have two customers
with the same ID.
2.5 Inheritance (optional)
Apply the inheritance in your application where possible.