quarkusio/quarkus · error · IllegalStateException

runtime config has already been set

Error message

runtime config has already been set

What it means

Deployment.setRuntimeConfiguration is idempotent-by-first-write: once a RuntimeConfiguration has been installed on a Deployment, calling setRuntimeConfiguration again throws this IllegalStateException. The deployment refuses to swap runtime configuration after it has been set, to keep configuration consistent for the live application.

Source

Thrown at independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/Deployment.java:209

    public ThreadSetupAction getThreadSetupAction() {
        return threadSetupAction;
    }

    public RequestContextFactory getRequestContextFactory() {
        return requestContextFactory;
    }

    public List<GenericRuntimeConfigurableServerRestHandler<?>> getRuntimeConfigurableServerRestHandlers() {
        return runtimeConfigurableServerRestHandlers;
    }

    public RuntimeConfiguration getRuntimeConfiguration() {
        return runtimeConfiguration;
    }

    public Deployment setRuntimeConfiguration(RuntimeConfiguration runtimeConfiguration) {
        if (this.runtimeConfiguration != null) {
            throw new IllegalStateException("runtime config has already been set");
        }
        this.runtimeConfiguration = runtimeConfiguration;
        return this;
    }

    public Map<String, List<String>> getDisabledEndpoints() {
        return disabledEndpoints;
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Call setRuntimeConfiguration exactly once per Deployment instance; create a new Deployment if configuration must change.
2. Guard your bootstrap code with an 'initialized' flag or check deployment.getRuntimeConfiguration() != null before setting.
3. In tests, rebuild the Deployment object for each test rather than reusing and reconfiguring a shared instance.

Example fix

// before
deployment.setRuntimeConfiguration(cfg); // called twice in restart path
// after
if (deployment.getRuntimeConfiguration() == null) {
    deployment.setRuntimeConfiguration(cfg);
}

if (deployment.getRuntimeConfiguration() != null) {
    // skip re-setting, or replace the whole Deployment
} else {
    deployment.setRuntimeConfiguration(runtimeConfig);
}

try {
    deployment.setRuntimeConfiguration(cfg);
} catch (IllegalStateException e) {
    if ("runtime config has already been set".equals(e.getMessage())) {
        log.warn("Runtime configuration already set; reusing existing configuration");
    } else {
        throw e;
    }
}

When it happens

Trigger: Calling createApplication-style bootstrapping code that invokes deployment.setRuntimeConfiguration(cfg) more than once on the same Deployment instance — e.g. a custom bootstrap, dev-mode restart path, or test harness that re-sets config.

Common situations: Custom embedding of RESTEasy Reactive (not via Quarkus) where the setup code is accidentally executed twice; test frameworks building the Deployment in @BeforeEach without recreating the Deployment object; double initialization after a runtime reload.

Related errors

• Handler '${handlerClassName}' has not been properly configur
• Setting both 'readBody' and 'preMatching' to 'true' on '@Ser
• Setting both '@WithFormRead' and 'preMatching' to 'true' on
• Could not load exception mapper
• Failed to load application configuration

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/a3137b1e1cc31ce4. Report an issue: GitHub.