code: public static List<Kontonummer> getKontonummerListForAccountType(String accountType, int length) {
  		KontonummerValidator.validateAccountTypeSyntax(accountType);
  		final class AccountTypeKontonrDigitGenerator extends KontonummerDigitGenerator {
  			private final String accountType;
  
  			AccountTypeKontonrDigitGenerator(String accountType) {
  				this.accountType = accountType;
  			}
  
  			@Override
  			String generateKontonummer() {
  				StringBuilder kontonrBuffer = new StringBuilder(LENGTH);
  				for (int i = 0; i < LENGTH;) {
  					if (i == ACCOUNTTYPE_START_DIGIT) {
  						kontonrBuffer.append(accountType);
  						i += accountType.length();
  					} else {
  						kontonrBuffer.append((int) (Math.random() * 10));
  						i++;
  					}
  				}
  				return kontonrBuffer.toString();
  			}
  		}
  		return getKontonummerListUsingGenerator(new AccountTypeKontonrDigitGenerator(accountType), length);
  	}
docs: Returns a List with random but syntactically valid Kontonummer instances
  for a given AccountType.
  
  @param accountType
  A String representing the AccountType to use for all
  Kontonummer instances
  @param length
  Specifies the number of Kontonummer instances to create in the
  returned List
  @return A List with Kontonummer instances