java.net.ConnectException: Connection refused

Java.net.ConnectException, commonly referred to as "connection refused," is a frequently encountered exception in Java networking. This issue occurs when a client tries to establish a connection with a server that either isn't accepting connections or cannot be reached.

  1. Explanation of the Problem

A client may face this error when attempting to create a connection with a server that is not ready to accept incoming connections. The server might be down, experiencing a high volume of traffic, or not running the service the client is trying to access.

  1. Common Reasons for Connection Refusal

There are several reasons why a server might refuse a client's connection attempt, such as:

a. The server is not running: If the server application is not active, it won't accept incoming connections. b. An incorrect port number: A mismatched port number between the client and server will result in a connection refusal. c. Firewall restrictions: Firewalls can block incoming connections if not configured properly.

  1. How to Address the Issue

To resolve the connection refusal problem, follow these steps:

a. Verify the server is operational: Ensure the server application is running and capable of accepting connections. b. Double-check the port number: Make sure both the client and server are using the same port number for communication. c. Configure the firewall: Ensure the firewall is set up to allow incoming connections on the specified port.