Allow setting the ScheduledThreadPoolExecutor.

src/main/java/com/zaxxer/hikari/HikariConfig.java

@@ -26,6 +26,7 @@ import java.nio.file.Paths;
 import java.util.Properties;
 import java.util.Set;
 import java.util.TreeSet;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -87,6 +88,7 @@ public class HikariConfig implements HikariConfigMBean
    private DataSource dataSource;
    private Properties dataSourceProperties;
    private ThreadFactory threadFactory;
+   private ScheduledThreadPoolExecutor scheduledExecutor;
    private Object metricRegistry;
    private Object healthCheckRegistry;
    private Properties healthCheckProperties;
@@ -643,6 +645,26 @@ public class HikariConfig implements HikariConfigMBean
       this.poolName = poolName;
    }
 
+   /**
+    * Get the ScheduledExecutorService used for housekeeping.
+    *
+    * @return the executor
+    */
+   public ScheduledThreadPoolExecutor getScheduledExecutorService()
+   {
+      return scheduledExecutor;
+   }
+
+   /**
+    * Set the ScheduledExecutorService used for housekeeping.
+    *
+    * @param executor the ScheduledExecutorService
+    */
+   public void setScheduledExecutorService(ScheduledThreadPoolExecutor executor)
+   {
+      this.scheduledExecutor = executor;
+   }
+
    public String getTransactionIsolation()
    {
       return transactionIsolationName;

src/main/java/com/zaxxer/hikari/pool/HikariPool.java

@@ -148,10 +148,15 @@ public class HikariPool implements HikariPoolMBean, IBagStateListener
       this.closeConnectionExecutor = createThreadPoolExecutor(4, "HikariCP connection closer (pool " + config.getPoolName() + ")", config.getThreadFactory(), new ThreadPoolExecutor.CallerRunsPolicy());
 
       ThreadFactory threadFactory = config.getThreadFactory() != null ? config.getThreadFactory() : new DefaultThreadFactory("Hikari Housekeeping Timer (pool " + config.getPoolName() + ")", true);
-      this.houseKeepingExecutorService = new ScheduledThreadPoolExecutor(1, threadFactory, new ThreadPoolExecutor.DiscardPolicy());
-      this.houseKeepingExecutorService.scheduleAtFixedRate(new HouseKeeper(), HOUSEKEEPING_PERIOD_MS, HOUSEKEEPING_PERIOD_MS, TimeUnit.MILLISECONDS);
-      this.houseKeepingExecutorService.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
-      this.houseKeepingExecutorService.setRemoveOnCancelPolicy(true);
+      if (config.getScheduledExecutorService() != null) {
+         this.houseKeepingExecutorService = config.getScheduledExecutorService();
+      }
+      else {
+         this.houseKeepingExecutorService = new ScheduledThreadPoolExecutor(1, threadFactory, new ThreadPoolExecutor.DiscardPolicy());
+         this.houseKeepingExecutorService.scheduleAtFixedRate(new HouseKeeper(), HOUSEKEEPING_PERIOD_MS, HOUSEKEEPING_PERIOD_MS, TimeUnit.MILLISECONDS);
+         this.houseKeepingExecutorService.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
+         this.houseKeepingExecutorService.setRemoveOnCancelPolicy(true);
+      }
       this.leakTask = (config.getLeakDetectionThreshold() == 0) ? LeakTask.NO_LEAK : new LeakTask(config.getLeakDetectionThreshold(), houseKeepingExecutorService);
 
       poolUtils.setLoginTimeout(dataSource, connectionTimeout);