How can I set a timer in Java to attempt a database connection for 2 minutes before throwing an exception?

General Discussions
2

A great way to implement a Java timer for your database connection is by using ScheduledExecutorService, which allows you to run tasks at fixed intervals while keeping track of elapsed time.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.concurrent.*;

public class DatabaseConnector {
    public static void main(String[] args) {
        ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
        long startTime = System.currentTimeMillis();
        
        Runnable task = () -> {
            try {
                Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
                System.out.println("Connected successfully!");
                scheduler.shutdown();
            } catch (SQLException e) {
                if (System.currentTimeMillis() - startTime > 120_000) { // 2-minute limit
                    scheduler.shutdown();
                    throw new RuntimeException("Failed to connect within 2 minutes.", e);
                }
                System.out.println("Retrying...");
            }
        };

        scheduler.scheduleAtFixedRate(task, 0, 5, TimeUnit.SECONDS); // Retry every 5 seconds
    }
}

:white_check_mark: Why use this?

  • Precise timing using scheduled retries.
  • Non-blocking, allowing the program to continue running.
  • Exception thrown properly after 2 minutes.

:rotating_light: When to avoid?

If your database connection should block until success or timeout.