Please help with correct this below switch / case block java code, so the same ssn not can be entered by a user mistakenly again, when a new customer is registered by the user.

The problem is when the user add /registered a new customer, still the same ssn can be used/entered.

I don't have any compiler errors, but the if/else block doesn't work,

the user can sill type in same ssn that have been entered before when a another customer

was added/registered.

Thanks!

HashSet hashSet = new HashSet(); switch (choice) { case 1: { System.out.print("Enter customer unique ssn: "); ssn = sc.nextInt(); if (hashSet.contains(ssn)) { System.out.println("Ssn already exists"); } else { hashSet.add(ssn); System.out.print("Enter customer name: "); sc.nextLine(); String name = sc.nextLine(); Customer customer = new CustomerBuilder().setSsn(ssn).setName(name).createCustomer(); Bank.addCustomer(customer); System.out.println(" Customer added successfully with uniquely ssn: " + customer.getSSN()); } } break;