A example code which created for a stackoverflow question https://stackoverflow.com/q/50691564/2940265

Assignment.java

package com;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
import static java.lang.System.out;

public class Assignment
{
    public static void main(String[] args)
    {
        try
        {
            new
                    BankAccountApp("C:\\Users\\hSenid\\IdeaProjects\\JavaTest\\src\\dsds");
        }
        catch (IOException ioe)
        {
            out.printf("Missing file: %sC:/Users/USER/workspace/assignment/data/AssignmentData? \n\n",
                    new Assignment().getClass().getPackage().getName());
        }
    }
}

class BankAccountApp
{
    private List<BankAccount> accounts;
    public BankAccountApp(String filename) throws IOException
    {
        readAccountData(filename);
        displayMenu();
        int opt = 0;
        try (Scanner input = new Scanner(System.in))
        {
            while (true)
            {
                out.print("\nSelect an option: ");
                opt = input.nextInt();// format exception if string
                if (opt < 0 || opt > 7)
                    out.println("Invalid. Must be 1 - 7 (or 0 for menu).");
                else
                    break;
            }
        }
        switch (opt)
        {
            case 0: displayMenu(); break;
            case 1: doDeposit(); break;
            case 2: doWithdraw(); break;
            case 3: displayHighestBalanceAccount(); break;
            case 4: displayMostActiveAccount(); break;
            case 5: displayAllAccounts("C:/Users/USER/workspace/assignment/data/AssignmentData"); break;
            case 6:
            {
                int total = getTotalTransactions(accounts);
                out.println("Total transactions: " + total);
                break;
            }
            case 7: farewell(); return;
        }
    }
    public void readAccountData(String fn) throws IOException
    {
        accounts = new LinkedList<>();
        Path path = new File("C:/Users/USER/workspace/assignment/data/AssignmentData").toPath();
        List<String> content = Files.readAllLines(path);
        for(String line : content){
            String[] items = line.split(",");
            String name = items[0];
            int age = Integer.valueOf(items[1]);
            String accountID = items[2];
            double balance = Double.valueOf(items[3]);
            int accountType = Integer.valueOf(items[4]);
            BankAccount b = new BankAccount(name, age, accountID, balance, accountType);
            accounts.add(b);
        }
    }

    public void displayAllAccounts(String fn) throws IOException
    {
        accounts = new LinkedList<BankAccount>();
        Path path = new File(fn).toPath();
        List<String> content = Files.readAllLines(path);
        for(String line : content){
            String[] items = line.split(",");
            String name = items[0];
            int age = Integer.valueOf(items[1]);
            String accountID = items[2];
            double balance = Double.valueOf(items[3]);
            int accountType = Integer.valueOf(items[4]);
            BankAccount b = new BankAccount(name, age, accountID, balance, accountType);
            accounts.add(b);
            out.printf("---All Bank Accounts---\n");
            out.println("Name: "+name);
            out.println("Age: "+age);
            out.println("Account ID: "+accountID);
            out.printf("Account Balance: %f",balance);
            out.println("\nAccount Type: "+accountType+"\n");
        }
        return;
    }
    public void displayHighestBalanceAccount()
    {
        BankAccount mostMoney = accounts.get(3);
        for(BankAccount b : accounts){
            if(mostMoney.getbalance() < b.getbalance()){
                mostMoney = b;
            }
        }
        String name = mostMoney.getname();
        int age = mostMoney.getage();
        String accountID = mostMoney.getaccountID();
        double balance = mostMoney.getbalance();
        int accountType = mostMoney.accountType();
        out.printf("---Bank account with the highest balance---\n");
        out.println("Name: "+name);
        out.println("Age: "+age);
        out.println("Account ID: "+accountID);
        out.printf("Account Balance: %f",balance);
        out.println("\nAccount Type: "+accountType);
    }
    public void displayMostActiveAccount()
    {

    }
    public int getTotalTransactions(List<BankAccount> list)
    {
        return 0;
    }
    public void doDeposit()
    {
        out.print("Enter an account ID for deposit: ");
    }
    public void doWithdraw()
    {
    }
    public void farewell()
    {
        out.println("Thanks for using the service. Bye!");
    }
    public void displayMenu()
    {
        out.println("*********************************");
        out.println("* Bank Account Operation Menu *");
        out.println("***********************************\n");
        out.println("0. Display Menu");
        out.println("1. Deposit");
        out.println("2. Withdraw");
        out.println("3. Display Highest Balance Account");
        out.println("4. Display Most Active Account");
        out.println("5. Display All Accounts");
        out.println("6. Display Total Number of Transactions");
        out.println("7. Exit");
    }
}
class BankAccount extends Person1
{
    private String accountID;
    private double balance;
    private int accountType;
    public BankAccount(String name, int age, String accountID, double balance, int accountType)
    {
        super(name, age);
        this.accountID = accountID;
        this.balance = balance;
        this.accountType = accountType;
    }

    public String getaccountID() {
        return accountID;
    }

    public void setaccountID(String accountID) {
        this.accountID = accountID;
    }

    public double getbalance() {
        return balance;
    }

    public void setbalance(double balance) {
        this.balance = balance;
    }

    public int accountType() {
        return accountType;
    }

    public void setaccountType(int accountType) {
        this.accountType = accountType;
    }
}
class Person1 {
    private String name;
    private int age;
    public Person1(String name, int age)
    {
        this.name = name;
        this.age = age;
    }

    public String getname() {
        return name;
    }

    public void setname(String name) {
        this.name = name;
    }

    public int getage() {
        return age;
    }

    public void setage(int age) {
        this.age = age;
    }
}