What causes "Could not evaluate standby mode" in quarkusio/quarkus?

Guard with isStarted() and check shutdown state before calling isRunning()

quarkusio/quarkus · warning · IllegalStateException

Could not evaluate standby mode

Error message

Could not evaluate standby mode

What it means

Quarkus throws this IllegalStateException when querying the underlying Quartz scheduler's standby state fails. Scheduler.isRunning() returns !scheduler.isInStandbyMode(); Quartz raises SchedulerException if the scheduler is shut down or its JobStore cannot be consulted, and Quarkus converts it into this unchecked exception.

Source

Thrown at extensions/quartz/runtime/src/main/java/io/quarkus/quartz/runtime/QuartzSchedulerImpl.java:459

            QuartzTrigger trigger = scheduledTasks.get(parsedIdentity);
            if (trigger != null) {
                scheduler.resumeJob(new JobKey(SchedulerUtils.lookUpPropertyValue(parsedIdentity), Scheduler.class.getName()));
                events.fireScheduledJobResumed(new ScheduledJobResumed(trigger));
            }
        } catch (SchedulerException e) {
            throw new RuntimeException("Unable to resume job", e);
        }
    }

    @Override
    public boolean isRunning() {
        if (!isStarted()) {
            return false;
        } else {
            try {
                return !scheduler.isInStandbyMode();
            } catch (SchedulerException e) {
                throw new IllegalStateException("Could not evaluate standby mode", e);
            }
        }
    }

    @Override
    public List<Trigger> getScheduledJobs() {
        if (!isStarted()) {
            throw notStarted();
        }
        return List.copyOf(scheduledTasks.values());
    }

    @Override
    public Trigger getScheduledJob(String identity) {
        if (!isStarted()) {
            throw notStarted();
        }
        Objects.requireNonNull(identity);

View on GitHub (pinned to e1c734241f)

Solutions

Guard with isStarted() and check shutdown state before calling isRunning()
Avoid calling isRunning() during application shutdown callbacks
Check the cause SchedulerException for a store-level failure and fix datasource connectivity
Use isStarted() (scheduler exists) rather than isRunning() when you only need lifecycle existence

Example fix

// before
boolean running = scheduler.isRunning();
// after
boolean running = scheduler.isStarted() && !isShuttingDown() ? safeIsRunning(scheduler) : false;

boolean safeIsRunning(Scheduler s) {
    try { return s.isRunning(); }
    catch (IllegalStateException e) { return false; }
}

Defensive patterns

Strategy: type-guard

Validate before calling

boolean safe = scheduler.isStarted();
// check scheduler state before calling isRunning()

Type guard

boolean isRunningSafe(io.quarkus.scheduler.Scheduler s) {
    if (s == null || !s.isStarted()) return false;
    try { return s.isRunning(); }
    catch (IllegalStateException e) { return false; }
}

Try / catch

try {
    boolean running = scheduler.isRunning();
} catch (IllegalStateException e) {
    boolean running = false; // treat as not-running during shutdown
}

Prevention

Avoid calling isRunning() inside shutdown hooks / @PreDestroy logic
Use isStarted() when you only need to know if a scheduler exists
Cache the running state instead of polling during shutdown

When it happens

Trigger: Calling Scheduler.isRunning() after the Quartz scheduler has been shut down (or is shutting down) or when the underlying store cannot answer isInStandbyMode() — e.g. during shutdown races or JDBC store failures.

Common situations: Calling isRunning() from a shutdown hook or Scheduled job executing during app shutdown; health checks racing the destroy() lifecycle; DB-backed store failing mid-query.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/c165e916aad01051. Report an issue: GitHub.