How to Resolve java.io.IOException: Server Returns HTTP Response Code 505

What does it mean when I encounter java.io.IOException: Server returns HTTP response code 505?

// Sample HTTP client code that may result in IOException
try {
    URL url = new URL("http://example.com/api");
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setRequestMethod("GET");
    int responseCode = connection.getResponseCode();
} catch (IOException e) {
    e.printStackTrace();
}

The java.io.IOException indicating a server returns HTTP response code 505 signifies that the server does not support the HTTP protocol version used in your request. This is generally due to compatibility issues between the client and server configurations.

// Correctly specify HTTP version
connection.setRequestProperty("Version", "HTTP/1.0"); // Example to set HTTP 1.0

Causes

• The server only accepts older HTTP versions (e.g., HTTP/1.0) while the client is attempting to use a newer version (HTTP/1.1 or above).
• Misconfiguration in the server settings that doesn't correctly handle HTTP requests.
• The client's library or framework is outdated and uses an unsupported HTTP version.

Solutions

• Verify that the HTTP version used in your request is supported by the server. You can specify it in your HttpURLConnection using setRequestProperty() method.
• Update the server configuration to allow for the HTTP version used by your client or roll back to a compatible version.
• Upgrade your HTTP client library or framework to a version that ensures compatibility with the server.

Mistake: Not checking server documentation for supported HTTP versions.

Solution: Always refer to server documentation to confirm the compatible HTTP version.

Mistake: Neglecting to update client libraries that impact HTTP communications.

Solution: Regularly update your client libraries, ensuring they are compatible with current server specifications.