diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/GetConfig.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/GetConfig.java
index f89f047..f31a567 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/GetConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/GetConfig.java
@@ -95,7 +95,7 @@
     return v ? v : null;
   }
 
-  public class ConfigInfo {
+  public static class ConfigInfo {
     public String info;
     public String onSuccess;
     public Boolean allowEmail;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/RefUpdateListener.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/RefUpdateListener.java
index 31d1a56..fef0bc7 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/RefUpdateListener.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/RefUpdateListener.java
@@ -26,6 +26,8 @@
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.util.concurrent.Future;
+
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
 import org.slf4j.Logger;
@@ -90,7 +92,8 @@
           }
         };
     if (cfg.getBoolean("createNotesAsync", false)) {
-      workQueue.getDefaultQueue().submit(task);
+      @SuppressWarnings("unused")
+      Future<?> possiblyIgnoredError = workQueue.getDefaultQueue().submit(task);
     } else {
       task.run();
     }