Making a Connection

Once a driver is on your classpath, the standard way to open a connection to a database is DriverManager.getConnection(url, user, password). It returns a Connection object, which represents a live session with the database and is the starting point for everything else in JDBC.

DriverManager.getConnection

import java.sql.*;

public class ConnectExample {
  public static void main(String[] args) throws Exception {
    Connection conn = DriverManager.getConnection(
      "jdbc:mysql://localhost:3306/coding_with_sonu", "root", "");

    System.out.println("Connected!");
    conn.close();
  }
}

Anatomy of a JDBC URL

The URL string tells DriverManager which driver to use and how to reach the database. Breaking down jdbc:mysql://localhost:3306/coding_with_sonu?useSSL=false&serverTimezone=UTC:

Always Close Your Connection

A Connection holds real resources — a network socket and server-side state. Forgetting to call .close() leaks connections and can exhaust your database's connection pool over time. Calling it manually works, but it's easy to skip when an exception is thrown partway through your code.

Try-With-Resources: the Recommended Pattern

Connection implements AutoCloseable, so the safest way to use one is inside a try-with-resources block. The connection is closed automatically when the block ends — whether it finishes normally or an exception is thrown.

import java.sql.*;

public class TryWithResourcesExample {
  public static void main(String[] args) {
    try (Connection conn = DriverManager.getConnection(
        "jdbc:mysql://localhost:3306/coding_with_sonu", "root", "")) {
      System.out.println("Connected!");
      // conn.close() is called automatically here, even on exception
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

Checking a Connection Is Still Valid

Connections can silently die (network blip, database restart). Before reusing a long-lived connection, you can check conn.isValid(timeout), which pings the database and returns true or false within the given timeout in seconds — handy for connection pools and health checks.