394215 - Scheduled tasks throwing exceptions kill java.util.Timer thread.

Wrapping the the task run() method into a try/catch to avoid that the Timer thread dies.

jetty-util/src/main/java/org/eclipse/jetty/util/thread/TimerScheduler.java

@@ -24,9 +24,13 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
+import org.eclipse.jetty.util.log.Log;
+import org.eclipse.jetty.util.log.Logger;
 
 public class TimerScheduler extends AbstractLifeCycle implements Scheduler
 {
+    private static final Logger LOG = Log.getLogger(TimerScheduler.class);
+
     /*
      * This class uses the Timer class rather than an ScheduledExecutionService because
      * it uses the same algorithm internally and the signature is cheaper to use as there are no
@@ -84,9 +88,16 @@ public class TimerScheduler extends AbstractLifeCycle implements Scheduler
 
         @Override
         public void run()
+        {
+            try
             {
                 _task.run();
             }
+            catch (Throwable x)
+            {
+                LOG.debug("Exception while executing task "+_task,x);
+            }
+        }
 
         @Override
         public String toString()

jetty-util/src/test/java/org/eclipse/jetty/util/thread/SchedulerTest.java

@@ -21,6 +21,7 @@ package org.eclipse.jetty.util.thread;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Random;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
@@ -174,6 +175,36 @@ public class SchedulerTest
         Assert.assertEquals(0,executed.get());
     }
 
+    @Test
+    public void testTaskThrowsException() throws Exception
+    {
+        long delay = 500;
+        Scheduler.Task task=_scheduler.schedule(new Runnable()
+        {
+            @Override
+            public void run()
+            {
+                throw new RuntimeException();
+            }
+        }, delay, TimeUnit.MILLISECONDS);
+
+        TimeUnit.MILLISECONDS.sleep(2 * delay);
+
+        // Check whether after a task throwing an exception, the scheduler is still working
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        _scheduler.schedule(new Runnable()
+        {
+            @Override
+            public void run()
+            {
+                latch.countDown();
+            }
+        }, delay, TimeUnit.MILLISECONDS);
+
+        Assert.assertTrue(latch.await(2 * delay, TimeUnit.MILLISECONDS));
+    }
+
     @Test
     @Slow
     public void testManySchedulesAndCancels() throws Exception