public class LocalClassExample {
  
  String regularExpression = "[^0-9]";
  
  public void validatePhoneNumber(/*final*/ String phoneNumber1,/*final*/ String phoneNumber2) {
    
    final int numberLength = 10;
     
    class PhoneNumber {
      
      String formattedPhoneNumber = null;

      PhoneNumber(String phoneNumber){        
        regularExpression = "[^0-9]";
        // numberLength = 7;
        String currentNumber = (phoneNumber).replaceAll(
          regularExpression, "");
        if (currentNumber.length() == numberLength)
          formattedPhoneNumber = currentNumber;
        else
          formattedPhoneNumber = null;
      }

      public String getNumber() {
        return formattedPhoneNumber;
      }
      
//    public void printOriginalNumbers() {
//      System.out.println("Original numbers are " + phoneNumber1 +
//          " and " + phoneNumber2);
//    }      
    }

    PhoneNumber myNumber1 = new PhoneNumber(phoneNumber1);
    PhoneNumber myNumber2 = new PhoneNumber(phoneNumber2);
    
//  myNumber1.printOriginalNumbers();
    
    if (myNumber1.getNumber() == null) 
      System.out.println("First number is invalid");
    else
      System.out.println("First number is " + myNumber1.getNumber());
    if (myNumber2.getNumber() == null)
      System.out.println("Second number is invalid");
    else
      System.out.println("Second number is " + myNumber2.getNumber());

  }

  public static void main(String... args) {
    LocalClassExample lce = new LocalClassExample();
    lce.validatePhoneNumber("123-456-7890", "456-7890");
  }
}