After much work on this code, regarding the checkUserPassword method. I can 1 error and cannot seem to find what the problem is. What must be done to fix my code? I am also not understanding what this error message means

import java.util.Scanner;  // Import the Scanner class
import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.Pattern;

class Main{
    
//checkUserName Method 
static boolean checkUserName(String userName) {
    boolean underscore = userName.contains("_");
    if (userName.length() <= 5 && underscore == true) {
        System.out.println("Username successfully captured \n");
        return true;
    }
    else{
        System.out.println("Username is not correctly formatted, please ensure that your username contains an underscore and is no more than 5 characters in length \n");
    }
    return false;
}

//checkUserPassword Method (At least eight characters long, Contain a capital letter, Contain a number, Contain a special character) 
static boolean checkUserPassword(String password, List<String> errorList) {

    Pattern specailCharPatten = Pattern.compile("[^a-z0-9 ]", Pattern.CASE_INSENSITIVE);
    Pattern UpperCasePatten = Pattern.compile("[A-Z ]");
    Pattern lowerCasePatten = Pattern.compile("[a-z ]");
    Pattern digitCasePatten = Pattern.compile("[0-9 ]");
    errorList.clear();

    boolean flag=true;

    
    if (password.length() < 8) {
        errorList.add("Password lenght must have alleast 8 character !!");
        flag=false;
    }
    if (!specailCharPatten.matcher(password).find()) {
        errorList.add("Password must have atleast one specail character !!");
        flag=false;
    }
    if (!UpperCasePatten.matcher(password).find()) {
        errorList.add("Password must have atleast one uppercase character !!");
        flag=false;
    }
    if (!lowerCasePatten.matcher(password).find()) {
        errorList.add("Password must have atleast one lowercase character !!");
        flag=false;
    }
    if (!digitCasePatten.matcher(password).find()) {
        errorList.add("Password must have atleast one digit character !!");
        flag=false;
    }
    
    


    return flag;

}

//registerUser method 
static Boolean registerUser(){

    return true;
}
//
//loginUser method
static Boolean loginUser(){
    return true;
}
//
//returnLoginStatus method
static Boolean returnLoginStatus(){
    return true;
}
//

public static void main(String[] args) {
    System.out.println("Welcome to the User Register program! \n");
    Scanner firstname1 = new Scanner(System.in); // Create a Scanner object
    System.out.println("Enter firstname: ");
    String firstName;
    firstName = firstname1.nextLine(); // Read user input from keyboard
    
    Scanner surname1 = new Scanner(System.in); // Create a Scanner objec
    System.out.println("Enter surname: ");
    String surName;
    surName = surname1.nextLine(); // Read user input from keyboard
    
    List<String> errorList = new ArrayList<String>();
    
    Scanner name1 = new Scanner(System.in); // Create a Scanner object
    System.out.println("Enter username: ");
    String userName;
    userName = name1.nextLine(); // Read user input
    checkUserName(userName);// call method 
    Scanner passw1= new Scanner(System.in);// Create a Scanner object
    System.out.println("Enter password:  ");
    String password;
    password= passw1.nextLine(); //Read user input
    List<String> errorList = new ArrayList<String>();
    checkUserPassword("hello", errorList);
    System.out.println(errorList);// call method 
    
    System.out.println("Welcome "  firstName " "  surName  " it is great to see you.");

}
}

The error I get is; Main.java:102: error: variable errorList is already defined in method main(String[]) List errorList = new ArrayList();

CodePudding user response：

You are declaring errorList 2 times in your main function, line 91 and line 102, Note that Java is a strongly typed language and one variable can have only one declaration in a scope, change the second one to errorList1 or something else and it should work fine