Casting one class object as anoter class object

[jdw_1968]

Hi,
I am using java 8SE. I am trying to loop through a hashmap of objects(of class Person). There are subclasses of Person called Instructor and Student. As I loop through the map, I am trying to see if I have a match of class Instructor, and cast that Person object as Instructor, so that I may use its methods.

I keep getting the following runtime error:
java.lang.ClassCastException: java.util.HashMap$Node cannot be cast to uStaff.Instructor
at uStaff.PersonApp.menu(PersonApp.java:108)
at uStaff.PersonApp.main(PersonApp.java:21)

Here is a code snippet:

//Instantiate the different Person, student and instructor objects
		Person thisPerson = new Person(01,fName,mName,lName,email,ssn,age);
		Student thisStudent = new Student(02,"Stacey","Marie","Morgan","smorgan@gmail.com","213-45-6789",20);
		thisStudent.setMajor("music");
		Instructor thisInstructor = new Instructor(03,"Joe","Douglass","Wells","joe@drumhaven.com","555-98-3029",46);
		thisInstructor.setDepartment("Computer Science");
		
		//Create hashmap of the different objects
		HashMap<Integer,Person> Ustaff = new HashMap<Integer,Person>();
		Ustaff.put(01, thisPerson);
		Ustaff.put(02, thisStudent);
		Ustaff.put(03, thisInstructor);
	
		
		for (Map.Entry<Integer, Person> entry : Ustaff.entrySet()){
			
			
			System.out.println( entry.getValue().toString() + " " +  " \n " + entry.getValue().getEmailDomain() + "\n " + entry.getValue().getLast4SSN() + "\n");
				
					
			if (entry.getValue().getClass().getSimpleName().equals("Instructor")) 
			{
				System.out.println(((Instructor)entry).getDepartment());
			}
			
			//+ ((Instructor) entry.getValue()).getDepartment() + " " + ((Student) entry.getValue()).getMajor());
			
			if (entry.getValue().getAge() >= entry.getValue().getEldest()) {
				System.out.println("Oldest\n");
			}
			else {
				System.out.println("Not the oldest\n");
			}
		}
	 
		}
				
	}

}

Im not quite sure what i am doing wrong.

[Norm]

The Map.Entry object contains the key and value. To get either, you need to call a get method that returns the object you want. See the API doc for a description.

[jdw_1968]

Thanks!