I could use some help here. I tried to modified the java codes to do what I'm asked to do. here it is
This project consists of three complete and individual subprojects (you need to work in the same subfolder for this assignment). Hints: to write objects with an ObjectOutputStream, the objects classes must implement interface Serializable; coderelated to processing object streams might throw exceptions and these exceptions must be caught.
1) Modify the Employee hierarchy from Figs. 10.4–10.8 to enable serialization of the classes in the hierarchy. Then, modify the application of Fig. 10.9 to output each object in the array employees to a file using object serialization.
2) Modify the application of Fig. 10.9 to read the objects in the file EmployeeData.ser into an array called employees, then output the contents of the array polymorphically as in Fig. 10.9.
3) Since arrays are objects in Java, entire arrays of Serializable objects can be output simply by passing an array’s name to an ObjectOutputStream’s writeObject method. Similarly, an entire array of Serializable objects can be read with a single call to an ObjectInputStream’s readObject method. Modify class OutputEmployees from the above step 1 to write the entire array to the file with a single output statement. Then, modify class InputEmployees from the above step 2 to read the entire array with a single statement.