Maps with multiple types of values in java

Question

I have to accomplish a strange peculiar scenario. Its described as follows:

I have to design a Map where the \'Keys\' are always of String

Answer 1

Why not make a PhoneNumber wrapper class that exposes an API for soring either one or multipel phone numbers and then can retrieve either one or all (multiple) phone numbers and then make a map of String and PhoneNumber? Something like:

class PhoneNumber {


  private String[] phoneNumbers;


  public void storePhoneNumber(String... phoneNumbers) {
     this.phoneNumbers = phoneNumbers;
  }

  public String getPhoneNumber() {
    if(phoneNumbers.length>=1) {
      return phoneNumbers[0];
    } else {
      return null;
    }

  }

  public List getPhoneNumbers() {
    if(phoneNumbers!=null) {
      return Arrays.asList(phoneNumbers);
    } else {
      return null;
    }

  }

}