VALIDATIONS.  Coursera DUKE UNIVE 102

package validations;
class WorkForce {
String firstName;
String lastName;
}
class WorkForceValidations {
public String nameValidations(WorkForce w, String firstName, String lastName) throws
InvalidNameException,Exception {
if (firstName == null && lastName == null) {
throw new NullPointerException("Entry missing");
} else if (firstName.length() == 0 && lastName.length() == 0) {
throw new Exception("Index Out of Bound");
} else if (Character.isDigit(firstName.charAt(0)) &&
Character.isDigit(lastName.charAt(0))) {
throw new InvalidNameException("First Character is invalid");
}
else {
w.firstName=firstName;
w.lastName=lastName;
return firstName.concat(lastName);