Console-Based Banking System (Java)

Overview

This is a simple console banking application written in Java. It demonstrates object-oriented design, menu-driven flow, and exception handling using an in-memory account store.

All logic is currently implemented in a single source file: Bank.java.

Features

• Create a new account with name and initial balance
• Auto-generate account numbers (starting from 1000)
• Access existing accounts using account number
• Deposit money
• Withdraw money
• Check current balance
• Handle common errors gracefully:
  • negative/zero deposit or withdrawal
  • negative initial balance
  • insufficient balance
  • invalid menu choices

Current Structure

The project currently contains:

• Bank.java

Inside Bank.java, the following classes are defined:

• InsufficientFundsException
• BankAccount
• BankService
• AccountMenu
• Bank (main entry point)

How It Works

1. User sees the main menu:
   • Create new account
   • Access existing account
   • Exit
2. On account creation, a new account number is generated and stored in memory.
3. After creating or opening an account, user enters account operations menu:
   • Deposit
   • Withdraw
   • Check balance
   • Exit
4. Data is stored only for the current runtime session.

Run Instructions

Compile and run:

javac Bank.java
java Bank

Notes

• No database or file persistence is used.
• Accounts are stored in a HashMap<Integer, BankAccount>.
• This project is intended for Java fundamentals practice.