Question

Write Java program:

• Is at least 8 characters long • Contains at least 1 lower letter character • Contains at least 1 upper letter character • Contains at least 1 numeric digit • Contains at least 1 special character from the set: !@#$%^&* • Does not contain the word “and” or the word “the” Prompts the user for a password, including the requirements above in your output. Output a string that states valid or invalid. If invalid, state which rules from the list above have not been met, and prompt the user to enter another password. Utilize the following functionality: • indexOf • Looping structure • charAt() • isDigit() • isUpperCase() • isLowerCase() • and any additional functionality needed

Answer 1

PasswordChecker.java

import java.util.*;
class PasswordChecker
{
public static boolean isValid(String password)
{
String symbol = "!@#$%^&*";
int upperCaseCount = 0;
int lowerCaseCount = 0;
int digitCount = 0;
boolean hasSymbol = false;
if(password.length() >= 8) {//Checks for length.
int i = 0;
while( i < password.length()) //For each character.
{
char c = password.charAt(i);
if(Character.isUpperCase(c) ) //If uppercase, increment counter.
upperCaseCount++;
if(Character.isLowerCase(c)) //If lowercase, increment counter.
lowerCaseCount++;
if(Character.isDigit(c)) //If digit, increment counter.
digitCount++;
if(symbol.indexOf(c) != -1 && hasSymbol == false) //If has symbol, mark flag.
hasSymbol = true;
i++;
}
} else {
System.out.println("Invalid password. Password length should be no less than 8.");
return false;
}
if(upperCaseCount < 1) {
System.out.println("Invalid password. Password should contain minimum 1 uppercase letter.");
return false;
}
if(lowerCaseCount < 1) {
System.out.println("Invalid password. Password should contain minimum 1 lowercase letter.");
return false;
}
if(digitCount < 1) {
System.out.println("Invalid password. Password should contain minimum 1 digits.");
return false;
}
if(!hasSymbol) {
System.out.println("Invalid password. Password should contain atleast one special characters from ! @ # $ % ^ & * ");
return false;
}
return true;
}
public static void main(String args[]){
   Scanner scan = new Scanner(System.in);
   System.out.print("Ennter the password: ");
   String pass = scan.next();
   while(!isValid(pass)){
       System.out.print("Ennter the password: ");
   pass = scan.next();
          
   }
   System.out.println("Given password is valid");
}
}

Output:

Ennter the password: pass
Invalid password. Password length should be no less than 8.
Ennter the password: password
Invalid password. Password should contain minimum 1 uppercase letter.
Ennter the password: Password
Invalid password. Password should contain minimum 1 digits.
Ennter the password: Password12
Invalid password. Password should contain atleast one special characters from ! @ # $ % ^ & *
Ennter the password: Password12!@
Given password is valid