public Response addCustomer(Customer customer) {
    System.out.println("----invoking addCustomer, Customer name is: " + customer.getName());
    customer.setId(++currentId);

    customers.put(customer.getId(), customer);

    return Response.ok(customer).build();
  }
 final void init() {
   Customer c = new Customer();
   c.setName("John");
   c.setId(123);
   customers.put(c.getId(), c);
 }