🔗 Connecting Java to AWS RDS (MySQL) – My Real-World Journey

A beginner-friendly walkthrough of setting up an AWS RDS MySQL database, connecting it to Java via JDBC, and resolving common pitfalls.

🛠️ Why I Did This

As part of building a full-stack automation project, I wanted to store user registration data in a database that could be accessed from my backend (Java). Instead of using a local database, I chose AWS RDS (MySQL) to simulate a real-world cloud environment.

🚧 The Problem I Faced

I successfully created the database instance on AWS RDS and attempted to connect to it from MySQL Workbench and Java using JDBC. However:

❌ I couldn't connect to the RDS instance initially via Workbench.

So I tried something different.

🧪 My First Workaround

I created a new database with the same name locally in MySQL Workbench (e.g., database-automation). After doing this, Workbench showed the database and allowed queries.

Later, I realized...

💡 The Real Fix

Here’s what I had missed:

🔐 1. RDS Security Group Inbound Rule

• AWS RDS blocks all public traffic by default.

• I had to allow inbound traffic to port 3306 from my machine’s IP.

  • In AWS Console:

    • Go to EC2 > Security Groups

    • Find the SG attached to your RDS

    • Edit inbound rules:

    •   Type: MySQL/Aurora
        Port: 3306
        Source: My IP (or 0.0.0.0/0 for public — not recommended)
      

    • 🔗 2. Correct JDBC URL

        javaCopyEditString url = "jdbc:mysql://database-automation.<xyz>.rds.amazonaws.com:3306/automa
      

      ✅ 3. Valid Credentials

      Ensure you use the RDS username and password that were set while creating the instance.

💻 JDBC Connection in Java

Here’s how I connected to the database from my Java class:

Connection conn = DriverManager.getConnection(
    "jdbc:mysql://<your-endpoint>:3306/automation_db", 
    "username", 
    "password"
);

String query = "INSERT INTO users (username, email, password) VALUES (?, ?, ?)";
PreparedStatement pstmt = conn.prepareStatement(query);
pstmt.setString(1, "john_doe");
pstmt.setString(2, "john@example.com");
pstmt.setString(3, "securePassword123");
pstmt.executeUpdate();

And it worked 🎉

📦 What I Learned

• AWS RDS is great for cloud-hosted DBs but needs correct network and security config

• Tools like MySQL Workbench help with visual interaction, but they’re not necessary for connecting via code

• Java JDBC integration is easy once you’ve resolved the connectivity issues