quarkusio/quarkus · error · IllegalStateException

Cannot reset a started application

Error message

Cannot reset a started application

What it means

ApplicationStateNotification tracks global dev-mode application state. reset() restores the INITIAL state between (re)deployments, but resetting an application that is currently STARTED would corrupt lifecycle tracking, so it is rejected with this IllegalStateException.

Solutions

1. Stop/shut down the running application before calling reset()
2. Use ApplicationStateNotification.waitForApplicationState(...) to confirm the app left STARTED state before resetting
3. Restructure restart logic to go through the framework's redeploy path instead of manual reset
4. Guard reset() behind a state check if you control the caller

Example fix

// before
ApplicationStateNotification.reset(); // throws if STARTED
// after
ApplicationStateNotification.waitForApplicationState(Duration.ofSeconds(10), State.STOPPED);
ApplicationStateNotification.reset();

// before reset
State s = ApplicationStateNotification.waitForApplicationState(Duration.ZERO, State.STOPPED, State.INITIAL);
if (s == State.STARTED) { /* stop application first */ }

try { ApplicationStateNotification.reset(); } catch (IllegalStateException e) { if (e.getMessage().contains("Cannot reset a started application")) { /* shut down app, then reset */ } else { throw e; } }

When it happens

Trigger: Calling ApplicationStateNotification.reset() while state == State.STARTED — e.g. a dev tool attempting to reset state without first stopping the running application, or a lifecycle race where restart logic runs before shutdown notification completes.

Common situations: Custom dev-mode tooling resetting state between hot reloads while the old instance still runs; test harnesses reusing state helpers across started applications.

Related errors

• All parameters have already been loaded, it is too late to…
• Bad ZIP entry
• Can only sync state on the server side of remote dev mode
• Cannot launch a runtime application with NORMAL launch mode
• Dev mode process did not complete successfully

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/5ac031c21155d2b3. Report an issue: GitHub.

Appendix: source

Thrown at core/devmode-spi/src/main/java/io/quarkus/dev/appstate/ApplicationStateNotification.java:20

/**
 * A class that allows for access to the application state, even from outside the runtime class loader.
 *
 * This should generally only be used by dev mode internals that need information about the current
 * application state.
 *
 * This class makes no attempt to verify that an application is starting/stopping when the
 * wait methods are called, this should only be called by a client that is controlling the Quarkus
 * lifecycle, and so knows what the current lifecycle state is.
 */
public class ApplicationStateNotification {

    private static State state = State.INITIAL;
    private static Throwable startupProblem;

    public static synchronized void reset() {
        if (state == State.STARTED) {
            throw new IllegalStateException("Cannot reset a started application");
        }
        state = State.INITIAL;
        startupProblem = null;
    }

    public static synchronized void notifyStartupComplete() {
        state = State.STARTED;
        ApplicationStateNotification.class.notifyAll();
    }

    public static synchronized void notifyApplicationStopped() {
        state = State.STOPPED;
        ApplicationStateNotification.class.notifyAll();
    }

    /**
     * Notify of startup failure.
     *

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