In Java, Password Pattern Validation
import java.util.Scanner; public class ValidatePassword{ public static void main(String[]args){ String pswd; int digi, uper, lowr; char[]chars = null; final int MIN = 2; final String ERROR = "%nError: At least %d %s is mandate!"; Scanner user = new Scanner(System.in); do{ digi = uper = lowr = 0; chars = null; System.out.print("\nEnter password: "); if(!user.hasNextLine()) break; pswd = user.nextLine(); if(null == pswd) break; chars = pswd.toCharArray(); for(char c: chars){ if(Character.isUpperCase(c)){ uper ++; } else if(Character.isLowerCase(c)){ lowr ++; } else if(Character.isDigit(c)){ digi ++; } } if(MIN > digi){ System.out.printf(ERROR, MIN, "digits"); } else if(MIN > uper){ System.out.printf(ERROR, MIN, "upper case"); } else if(MIN > lowr){ System.out.printf(ERROR, MIN, "lower case"); } else { break; } }while(true)...