Answer:
See Explaination
Step-by-step explanation:
import java.util.Scanner;
public class DocumentCodeTest {
 public static void main(String[] args) {
 Scanner scan = new Scanner(System.in);
 System.out.println("Enter the designation: ");
 String designation = scan.next();
 try{
 if (designation != null
 && (designation.charAt(0) == 'U'
 || designation.charAt(0) == 'C' || designation
 .charAt(0) == 'P') && designation.length() == 2) {
 System.out.println("Valid designation");
 }
 else{
 throw new InvalidDocumentCodeException("Invalid designation. Designation must be two characters and start with U, C or P.");
 }
 }
 catch(InvalidDocumentCodeException e){
 System.out.println(e);
 }
 }
}
InvalidDocumentCodeException.java
public class InvalidDocumentCodeException extends Exception{
 String errorMsg ;
 public InvalidDocumentCodeException(String s){
 this.errorMsg = s;
 }
public String toString(){
return (errorMsg ) ;
} 
}