testcontainers/testcontainers-java · warning

Unexpected error occurred - will proceed to try to wait…

Error message

Unexpected error occurred - will proceed to try to wait anyway

What it means

HttpWaitStrategy builds a formatted URI for logging and any RuntimeException thrown while doing so is caught and logged at WARN level. This is a non-fatal diagnostic: the strategy deliberately does not let a logging failure block the wait loop, so it proceeds to attempt the HTTP connection anyway. The underlying exception is attached to the warning for diagnosis.

Solutions

1. Inspect the attached exception stack trace to see which URI formatting step failed
2. Set an explicit port via waitingFor(new HttpWaitStrategy().forPort(8080)) so the raw URI port fallback is not needed
3. Ignore it if the container still becomes ready — the wait proceeds normally after this warning

Example fix

// before
new HttpWaitStrategy().forStatusCode(200) // relies on raw URI port parsing
// after
new HttpWaitStrategy().forPort(8080).forStatusCode(200)

// Ensure an explicit port is configured so raw URI parsing is not needed
if (waitStrategy instanceof HttpWaitStrategy) {
    ((HttpWaitStrategy) waitStrategy).forPort(8080);
}

// This warning is internal to the library; callers need no handling.
// If wrapping waits yourself:
try {
    waitUntilReady(container);
} catch (RuntimeException e) {
    // log and continue waiting, mirroring the strategy's own behavior
    log.warn("wait failed, continuing", e);
}

When it happens

Trigger: waitUntilReady catches any RuntimeException from constructing the log message (e.g. URI formatting/port extraction on a raw URI without a port). The message appears whenever that formatting code throws, regardless of whether the actual HTTP check succeeds.

Common situations: Containers exposing URIs with unusual formats (raw URIs without an explicit port, IPv6 literals, custom wait.forHttp paths); typically harmless noise during container startup with HttpWaitStrategy.

Related errors

• you cannot specify a value smaller than 1 ms
• HTTP response code was
• Response: did not match predicate
• Timed out waiting for URL to be accessible
• : No exposed ports or mapped ports - cannot wait for status

AI-assisted analysis of testcontainers/testcontainers-java@8e549514e3 (2026-09-12). Data as JSON: /api/errors/538362bb74a51958. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/testcontainers/containers/wait/strategy/HttpWaitStrategy.java:247

        try {
            // Un-map the port for logging
            int originalPort = waitStrategyTarget
                .getExposedPorts()
                .stream()
                .filter(exposedPort -> rawUri.getPort() == waitStrategyTarget.getMappedPort(exposedPort))
                .findFirst()
                .orElseThrow(() -> new IllegalStateException("Target port " + rawUri.getPort() + " is not exposed"));
            log.info(
                "{}: Waiting for {} seconds for URL: {} (where port {} maps to container port {})",
                containerName,
                startupTimeout.getSeconds(),
                uri,
                rawUri.getPort(),
                originalPort
            );
        } catch (RuntimeException e) {
            // do not allow a failure in logging to prevent progress, but log for diagnosis
            log.warn("Unexpected error occurred - will proceed to try to wait anyway", e);
        }

        // try to connect to the URL
        try {
            retryUntilSuccess(
                (int) startupTimeout.getSeconds(),
                TimeUnit.SECONDS,
                () -> {
                    getRateLimiter()
                        .doWhenReady(() -> {
                            try {
                                final HttpURLConnection connection = openConnection(uri);
                                connection.setReadTimeout(Math.toIntExact(readTimeout.toMillis()));

                                // authenticate
                                if (!Strings.isNullOrEmpty(username)) {
                                    connection.setRequestProperty(
                                        HEADER_AUTHORIZATION,

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