Tl; dr

Cualquier excepción que escape de su método run detiene todo el trabajo posterior, sin previo aviso.

Siempre use un try-catch dentro de su método run. Intente recuperarse si desea que la actividad programada continúe.

@Override
public void run ()
{
    try {
        doChore();
    } catch ( Exception e ) { 
        logger.error( "Caught exception in ScheduledExecutorService. StackTrace:\n" + t.getStackTrace() );
    }
}

El problema

La pregunta se refiere al truco crítico con un ScheduledExecutorService: Cualquier excepción lanzada o error que llegue al ejecutor hace que el ejecutor se detenga. No más invocaciones en el Ejecutable, no más trabajo hecho. Este trabajo el paro ocurre en silencio, no se le informará. Esta publicación de blog de lenguaje travieso entretenidamente narra la manera difícil de aprender sobre este comportamiento.

La Solución

La respuesta de yegor256 y la respuesta de arun_suresh ambas parecen ser básicamente correctas. Dos cuestiones con esas respuestas:

• Errores de captura, así como excepciones
• Un poco complicado

Errores y Excepciones ?

En Java normalmente solo captamos excepciones, no errores. Pero en este caso especial de ScheduledExecutorService, no atrapar cualquiera de los dos significará un paro laboral. Así que es posible que desee coger ambos. No estoy 100% seguro de esto, sin conocer completamente las implicaciones de detectar todos los errores. Por favor corríjame si es necesario.

Una forma de atrapar tanto excepciones como errores es capturar su superclase, Lanzable.

} catch ( Throwable t ) {

Rather más bien que...

} catch ( Exception e ) {

El enfoque más simple: Simplemente Agregue un Try-Catch

Pero ambas respuestas son un poco complicadas. Solo para el registro, voy a mostrar la solución más simple:

Siempre envuelva el código de su Ejecutable en un Try-Catch para capturar todos y cada uno de los errores de exceptions y.

Sintaxis Lambda

Con una lambda (en Java 8 y posteriores).

final Runnable someChoreRunnable = () -> {
    try {
        doChore();
    } catch ( Throwable t ) {  // Catch Throwable rather than Exception (a subclass).
        logger.error( "Caught exception in ScheduledExecutorService. StackTrace:\n" + t.getStackTrace() );
    }
};

Sintaxis anticuada

A la antigua usanza, antes de lambdas.

final Runnable someChoreRunnable = new Runnable()
{
    @Override
    public void run ()
    {
        try {
            doChore();
        } catch ( Throwable t ) {  // Catch Throwable rather than Exception (a subclass).
            logger.error( "Caught exception in ScheduledExecutorService. StackTrace:\n" + t.getStackTrace() );
        }
    }
};

En Cada ejecutable / Ejecutable

Independientemente de una ScheduledExecutorService, me parece sensato usar siempre un general try-catch( Exception† e ) en cualquier run método de a Runnable. Lo mismo para cualquier call método de un Callable.

Código de ejemplo completo

En el trabajo real, probablemente definiría el Runnable por separado en lugar de anidado. Pero esto lo convierte en un buen ejemplo de todo en uno.

package com.basilbourque.example;

import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

/**
 *  Demo `ScheduledExecutorService`
 */
public class App {
    public static void main ( String[] args ) {
        App app = new App();
        app.doIt();
    }

    private void doIt () {

        // Demonstrate a working scheduled executor service.
        // Run, and watch the console for 20 seconds.
        System.out.println( "BASIL - Start." );

        ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
        ScheduledFuture < ? > handle =
                scheduler.scheduleWithFixedDelay( new Runnable() {
                    public void run () {
                        try {
                            // doChore ;   // Do business logic.
                            System.out.println( "Now: " + ZonedDateTime.now( ZoneId.systemDefault() ) );  // Report current moment.
                        } catch ( Exception e ) {
                            // … handle exception/error. Trap any unexpected exception here rather to stop it reaching and shutting-down the scheduled executor service.
                            // logger.error( "Caught exception in ScheduledExecutorService. StackTrace:\n" + e.getStackTrace() );
                        }   // End of try-catch.
                    }   // End of `run` method.
                } , 0 , 2 , TimeUnit.SECONDS );


        // Wait a long moment, for background thread to do some work.
        try {
            Thread.sleep( TimeUnit.SECONDS.toMillis( 20 ) );
        } catch ( InterruptedException e ) {
            e.printStackTrace();
        }

        // Time is up. Kill the executor service and its thread pool.
        scheduler.shutdown();

        System.out.println( "BASIL - Done." );

    }
}

Cuando se ejecuta.

[23] ALBAHACA - Empezar.

Ahora: 2018-04-10T16:46:01.423286-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:03.449178-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:05.450107-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:07.450586-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:09.456076-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:11.456872-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:13.461944-07: 00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:15.463837-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:17.469218-07:00[America/Los_Angeles]

Ahora: 2018-04-10T16:46:19.473935-07:00[America/Los_Angeles]

[23] ALBAHACA-Hecho.

† O quizás Throwable en lugar de Exception para atrapar Error objetos también.

Sé que esta es una vieja pregunta, pero si alguien está usando delayed CompletableFuture con ScheduledExecutorService entonces debería manejar esto de esa manera:

private static CompletableFuture<String> delayed(Duration delay) {
    CompletableFuture<String> delayed = new CompletableFuture<>();
    executor.schedule(() -> {
        String value = null;
        try {
            value = mayThrowExceptionOrValue();
        } catch (Throwable ex) {
            delayed.completeExceptionally(ex);
        }
        if (!delayed.isCompletedExceptionally()) {
            delayed.complete(value);
        }
    }, delay.toMillis(), TimeUnit.MILLISECONDS);
    return delayed;
}

Y manejo de excepción en CompletableFuture:

CompletableFuture<String> delayed = delayed(Duration.ofSeconds(5));
delayed.exceptionally(ex -> {
    //handle exception
    return null;
}).thenAccept(value -> {
    //handle value
});

Otra solución sería tragar una excepción en el Runnable. Puede utilizar una conveniente VerboseRunnable clase de jcabi-log, por ejemplo:

import com.jcabi.log.VerboseRunnable;
scheduler.scheduleWithFixedDelay(
  new VerboseRunnable(
    Runnable() {
      public void run() { 
        // do business logic, may Exception occurs
      }
    },
    true // it means that all exceptions will be swallowed and logged
  ),
  1, 10, TimeUnit.SECONDS
);

Inspirado por la solución @ MBec, escribí un buen envoltorio genérico para el ScheduledExecutorService que:

• capturará e imprimirá cualquier excepción lanzada sin control.
• devolverá un Java 8 CompletableFuture en lugar de un Future.

:)

import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * This class use as a wrapper for the Native Java ScheduledExecutorService class.
 * It was created in order to address the very unpleasant scenario of silent death!
 * explanation: each time an unhandled exception get thrown from a running task that runs by ScheduledExecutorService
 * the thread will die and the exception will die with it (nothing will propagate back to the main thread).
 *
 * However, HonestScheduledExecutorService will gracefully print the thrown exception with a custom/default message,
 * and will also return a Java 8 compliant CompletableFuture for your convenience :)
 */
@Slf4j
public class HonestScheduledExecutorService {

    private final ScheduledExecutorService scheduledExecutorService;
    private static final String DEFAULT_FAILURE_MSG = "Failure occurred when running scheduled task.";

    HonestScheduledExecutorService(ScheduledExecutorService scheduledExecutorService) {
        this.scheduledExecutorService = scheduledExecutorService;
    }

    public CompletableFuture<Object> scheduleWithFixedDelay(Callable callable, String onFailureMsg, long initialDelay, long delay, TimeUnit unit) {
        final String msg = StringUtils.isEmpty(onFailureMsg) ? DEFAULT_FAILURE_MSG : onFailureMsg;
        CompletableFuture<Object> delayed = new CompletableFuture<>();

        scheduledExecutorService.scheduleWithFixedDelay(() -> {
            try {
                Object result = callable.call();
                delayed.complete(result);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        }, initialDelay, delay, unit);

        return delayed;
    }

    public CompletableFuture<Void> scheduleWithFixedDelay(Runnable runnable, String onFailureMsg, long initialDelay, long delay, TimeUnit unit) {
        final String msg = StringUtils.isEmpty(onFailureMsg) ? DEFAULT_FAILURE_MSG : onFailureMsg;
        CompletableFuture<Void> delayed = new CompletableFuture<>();

        scheduledExecutorService.scheduleWithFixedDelay(() -> {
            try {
                runnable.run();
                delayed.complete(null);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        }, initialDelay, delay, unit);

        return delayed;
    }

    public CompletableFuture<Object> schedule(Callable callable, String failureMsg, long delay, TimeUnit unit) {
        final String msg = StringUtils.isEmpty(failureMsg) ? DEFAULT_FAILURE_MSG : failureMsg;
        CompletableFuture<Object> delayed = new CompletableFuture<>();

        scheduledExecutorService.schedule(() -> {
            try {
                Object result = callable.call();
                delayed.complete(result);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        }, delay, unit);

        return delayed;
    }

    public CompletableFuture<Void> schedule(Runnable runnable, String failureMsg, long delay, TimeUnit unit) {
        final String msg = StringUtils.isEmpty(failureMsg) ? DEFAULT_FAILURE_MSG : failureMsg;
        CompletableFuture<Void> delayed = new CompletableFuture<>();

        scheduledExecutorService.schedule(() -> {
            try {
                runnable.run();
                delayed.complete(null);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        }, delay, unit);

        return delayed;
    }

    public CompletableFuture<Object> scheduleAtFixedRate(Callable callable, String failureMsg, long initialDelay, long period, TimeUnit unit) {
        final String msg = StringUtils.isEmpty(failureMsg) ? DEFAULT_FAILURE_MSG : failureMsg;
        CompletableFuture<Object> delayed = new CompletableFuture<>();

        scheduledExecutorService.scheduleAtFixedRate(() -> {
            try {
                Object result = callable.call();
                delayed.complete(result);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        }, initialDelay, period, unit);

        return delayed;
    }

    public CompletableFuture<Void> scheduleAtFixedRate(Runnable runnable, String failureMsg, long initialDelay, long period, TimeUnit unit) {
        final String msg = StringUtils.isEmpty(failureMsg) ? DEFAULT_FAILURE_MSG : failureMsg;
        CompletableFuture<Void> delayed = new CompletableFuture<>();

        scheduledExecutorService.scheduleAtFixedRate(() -> {
            try {
                runnable.run();
                delayed.complete(null);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        }, initialDelay, period, unit);

        return delayed;
    }

    public CompletableFuture<Object> execute(Callable callable, String failureMsg) {
        final String msg = StringUtils.isEmpty(failureMsg) ? DEFAULT_FAILURE_MSG : failureMsg;
        CompletableFuture<Object> delayed = new CompletableFuture<>();

        scheduledExecutorService.execute(() -> {
            try {
                Object result = callable.call();
                delayed.complete(result);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        });

        return delayed;
    }

    public CompletableFuture<Void> execute(Runnable runnable, String failureMsg) {
        final String msg = StringUtils.isEmpty(failureMsg) ? DEFAULT_FAILURE_MSG : failureMsg;
        CompletableFuture<Void> delayed = new CompletableFuture<>();

        scheduledExecutorService.execute(() -> {
            try {
                runnable.run();
                delayed.complete(null);
            } catch (Throwable th) {
                log.error(msg, th);
                delayed.completeExceptionally(th);
            }
        });

        return delayed;
    }

    public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
        return scheduledExecutorService.awaitTermination(timeout, unit);
    }

    public List<Runnable> shutdownNow() {
        return scheduledExecutorService.shutdownNow();
    }

    public void shutdown() {
        scheduledExecutorService.shutdown();
    }

}

Cualquier excepción en el run() de un hilo que se pasa a (ScheduledExecutorService) nunca se descarta y si usamos future.get () para obtener el estado, entonces el hilo principal espera infinitamente