Editing a Line!

package assign2;

import java.io.*;
import java.util.*;

public class RegAssignment2
{
    static Scanner sc = new Scanner(System.in);   
    public static void main(String args[]) throws FileNotFoundException, IOException, NullPointerException
    {
           String name="", answer, password="", newName, newPassword, newFirstname, newLastname, lines="---", menuAnswers="---", linesOld="---",editpass="---";            
           answer=login();
		if(answer.equals("b")) {
			name=getName();
			lines=findUser(name);}
                
		if(answer.equals("a")) {
			newName=getName();
			newPassword=getPassword();
			newFirstname=getFirst();
                        newLastname=getLast();
           
            try {
                 BufferedWriter bw = new BufferedWriter(new FileWriter("Password.txt", true)); 
                 bw.newLine();
                 bw.write(newName + " " + newPassword + " " + newFirstname+ " "+newLastname); 
                 bw.close();} 
            catch 
                 (IOException e){}
            
               System.out.println("\n                    Thank you for Registering!!");} 
                
                  if(lines!="---") {
                          String info[]=lines.split(" ");
                          linesOld=(info[1]);
                          password=getPassword();
                       if(password.equals(info[1])) 
                              menuAnswers=menu(info[1]);
                            else {
                                System.out.println("Wrong password! (Last Try)");
                                password=getPassword();
                                   if(password.equals(info[1])){
                                       menuAnswers=menu(info[1]);}
                                       else{
                                           System.out.println("EXITING...");}}
                                
		if(menuAnswers.equals("a")){
                }                
                
		if(menuAnswers.equals("b")){
                        }

                else {
                System.exit(2);
            }
		
		if(answer!="a" && answer!="b") {
                System.exit(2);}}}
    
        
	public static String login(){
		System.out.print("a) Register \nb) Login\n\n--> ");
		return sc.nextLine();}
        
	public static String getName(){
		System.out.print("\nEnter your Account Name     -->  ");
		return sc.nextLine();}
        
	public static String getPassword(){
		System.out.print("\nEnter your Account Password -->  ");
		return sc.nextLine();}
        
	public static String getFirst() {
		System.out.print("\nEnter your First Name       -->  ");
		return sc.nextLine();}
        
        public static String getLast() {
		System.out.print("\nEnter your Last Name        -->  ");
		return sc.nextLine();}
        
        public static String getnewPassword() {
                System.out.print("\nEnter your New Account Password -->  ");
                return sc.nextLine();}
        
        public static String findUser(String name)
        {
            try{
                Scanner scan = new Scanner(new File("Password.txt"));
                
                while(scan.hasNextLine()){
                        
                String lines=scan.nextLine();
                String info=lines.split(" ")[0];
                if(info.equals(name)){
                        return lines;}}}
            
                catch (FileNotFoundException eq)
                {System.out.println("\nPlease Register First");System.exit(2);}
            
                System.out.println("Incorrect Account(Try Again)");
                return "Incorrect Account(Try Again)";}        
        
        public static String menu(String info){
		System.out.println("\n                                  Menu");
		System.out.println("a) Change Password");
		System.out.println("b) Delete Account");
		System.out.print("\n--> ");
		String menuAnswers=sc.nextLine();
		return menuAnswers;}}

		if(menuAnswers.equals("a")){
                    String commanda = confirm();
                    if(commanda.equals("y")){
                        editPass=getnewPassword();
                        String findReplace[]=lines.split(" ");
                        findReplace[1]=String.valueOf(editPass);
                        String lines2=(findReplace[0]+ " " +findReplace[1]+ " " +findReplace[2]+ " " +findReplace[3]);
                
                        try {
                            BufferedWriter out = new BufferedWriter(new FileWriter("Password.txt"));
                            out.newLine();
                            out.write(lines2);
                            System.out.println("\nYour password has been changed!");
                            out.close();
                        } catch (IOException e){}}}