Replace ScheduledThreadPoolExecutor with ScheduledExecutorService

Follows how I2c1d895d503730bea4b4b635db7e04f4126453f8 is done.

Bug: Issue 7155
Change-Id: Ib8c6be8f5f5fd1213deef61de411499a5a01a380
diff --git a/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventModule.java b/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventModule.java
index 04b4abd..1098759 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventModule.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventModule.java
@@ -22,7 +22,7 @@
 import com.google.inject.Scopes;
 import com.google.inject.internal.UniqueAnnotations;
 
-import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ScheduledExecutorService;
 
 /** Configures handling for an event queue while providing its pool. */
 public class EventModule extends AbstractModule {
@@ -39,7 +39,7 @@
 
   @Provides
   @EventPool
-  ScheduledThreadPoolExecutor provideEventPool(EventQueue queue) {
+  ScheduledExecutorService provideEventPool(EventQueue queue) {
     return queue.getPool();
   }
 }
diff --git a/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventQueue.java b/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventQueue.java
index 2f96784..5ec6bfd 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventQueue.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/eventslog/EventQueue.java
@@ -18,12 +18,12 @@
 import com.google.gerrit.server.git.WorkQueue;
 import com.google.inject.Inject;
 
-import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ScheduledExecutorService;
 
 /** A queue for events to store. */
 public class EventQueue implements LifecycleListener {
   private final WorkQueue workQueue;
-  private ScheduledThreadPoolExecutor pool;
+  private ScheduledExecutorService pool;
 
   @Inject
   EventQueue(WorkQueue workQueue) {
@@ -46,7 +46,7 @@
     }
   }
 
-  ScheduledThreadPoolExecutor getPool() {
+  ScheduledExecutorService getPool() {
     return this.pool;
   }
 }