Note:
Please find the below LoginApplication class and coresponding output for three sample runs
Please revert back in case of any doubts or anything needs to be changed
Program:

package com.chegg;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Scanner;
public class LoginApplication {
// Global String variable to store input file name
public static final String INPUT_FILE_NAME = "userinfo.txt";
// Global HashMap to store user name and password
public static HashMap<String, String> userNamePasswordMap = new HashMap<String, String>();
// Global HashMap to store user name and full name
public static HashMap<String, String> userNameFullnameMap = new HashMap<String, String>();
public static void main(String[] args) {
//This method will read input text file and create user name & password map
//Also create user name & full name map
readInputFile ();
//Scanner input to read user input data
Scanner input = new Scanner(System.in);
//Variable to store attempt count
int attemptCount = 1;
//Iterating three times for user name and password
while (attemptCount<=3) {
System.out.print("Login: ");
String userName = input.nextLine();//Getting user name
System.out.print("Password: ");
String password = input.nextLine();//Getting password
//Checking weather user name exits and coresponding password is matching
if (userNamePasswordMap!= null & userNamePasswordMap.get(userName) != null
&& userNamePasswordMap.get(userName).equals(password)) {
//if matching then getting full name based on user name
String fullName = userNameFullnameMap.get(userName);
System.out.println("Welcome "+fullName);//Displaying welcome message
break;//breaking the loop
} else if (attemptCount <3){
//Displaying message for wrong user name or password
System.out.println("Either the username or password is incorrect. You have "+(3-attemptCount)+" more attempt.");
}
attemptCount ++;//increasing attempt count for wrong user name or password
}
//If 3 attempts over, displaying message
if (attemptCount >3) {
System.out.println("Sorry. Incorrect login. Please contact the system administrator.");
}
input.close();//Clossing input scanner
}
/**
* This method will read line by line of input text file to get each phone
* number. Then checking each phone number weather valid or in-valid. After
* that translated valid phone number to its numeric equivalent
*/
public static void readInputFile() {
BufferedReader inputReader = null;
try {
// create file object by file name
File file = new File(INPUT_FILE_NAME);
// creating input reader to read text file
inputReader = new BufferedReader(new FileReader(file));
String line = "";
// Iterating each line of input text file to get each user info
while ((line = inputReader.readLine()) != null) {
String[] lineArray = line.split(" ");//creating string array using space seperator
String userName = lineArray[lineArray.length-2];//getting user name from array
String password = lineArray[lineArray.length-1];//getting password from array
String fullName = "";
userNamePasswordMap.put(userName, password);//adding user name & password in map
//getting full name
for (int i=0;i<lineArray.length-2;i++) {
fullName = fullName + lineArray[i]+" ";
}
userNameFullnameMap.put(userName, fullName.trim());//adding user name & fullname in map
}
} catch (FileNotFoundException foe) {
foe.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (inputReader != null) {
inputReader.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

Output:
Sample Run 1

Sample Run 2

Sample Run 3