Shutdown executor and provide new endpoint constructor

graphql-java-kickstart/src/main/java/graphql/kickstart/execution/subscriptions/SubscriptionProtocolFactory.java

@@ -16,4 +16,8 @@ public String getProtocol() {
   }
 
   public abstract Consumer<String> createConsumer(SubscriptionSession session);
+
+  public void shutdown() {
+    // do nothing
+  }
 }

graphql-java-kickstart/src/main/java/graphql/kickstart/execution/subscriptions/apollo/ApolloSubscriptionConnectionListener.java

@@ -20,4 +20,8 @@ default void onStop(SubscriptionSession session, OperationMessage message) {
   default void onTerminate(SubscriptionSession session, OperationMessage message) {
     // do nothing
   }
-}
+
+  default void shutdown() {
+    // do nothing
+  }
+}

graphql-java-kickstart/src/main/java/graphql/kickstart/execution/subscriptions/apollo/ApolloSubscriptionKeepAliveRunner.java

@@ -61,4 +61,8 @@ void abort(SubscriptionSession session) {
       future.cancel(true);
     }
   }
+
+  void shutdown() {
+    this.executor.shutdown();
+  }
 }

graphql-java-kickstart/src/main/java/graphql/kickstart/execution/subscriptions/apollo/ApolloSubscriptionProtocolFactory.java

@@ -19,6 +19,7 @@ public class ApolloSubscriptionProtocolFactory extends SubscriptionProtocolFacto
   public static final int KEEP_ALIVE_INTERVAL = 15;
   @Getter private final GraphQLObjectMapper objectMapper;
   private final ApolloCommandProvider commandProvider;
+  private KeepAliveSubscriptionConnectionListener keepAlive;
 
   public ApolloSubscriptionProtocolFactory(
       GraphQLObjectMapper objectMapper,
@@ -67,7 +68,8 @@ public ApolloSubscriptionProtocolFactory(
     if (keepAliveInterval != null
         && listeners.stream()
             .noneMatch(KeepAliveSubscriptionConnectionListener.class::isInstance)) {
-      listeners.add(new KeepAliveSubscriptionConnectionListener(keepAliveInterval));
+      keepAlive = new KeepAliveSubscriptionConnectionListener(keepAliveInterval);
+      listeners.add(keepAlive);
     }
     commandProvider =
         new ApolloCommandProvider(
@@ -81,4 +83,11 @@ public ApolloSubscriptionProtocolFactory(
   public Consumer<String> createConsumer(SubscriptionSession session) {
     return new ApolloSubscriptionConsumer(session, objectMapper, commandProvider);
   }
+
+  @Override
+  public void shutdown() {
+    if (keepAlive != null) {
+      keepAlive.shutdown();
+    }
+  }
 }

graphql-java-kickstart/src/main/java/graphql/kickstart/execution/subscriptions/apollo/KeepAliveSubscriptionConnectionListener.java

@@ -6,7 +6,7 @@
 public class KeepAliveSubscriptionConnectionListener
     implements ApolloSubscriptionConnectionListener {
 
-  private final ApolloSubscriptionKeepAliveRunner keepAliveRunner;
+  protected final ApolloSubscriptionKeepAliveRunner keepAliveRunner;
 
   public KeepAliveSubscriptionConnectionListener() {
     this(Duration.ofSeconds(15));
@@ -35,4 +35,10 @@ public void onStop(SubscriptionSession session, OperationMessage message) {
   public void onTerminate(SubscriptionSession session, OperationMessage message) {
     keepAliveRunner.abort(session);
   }
+
+  @Override
+  public void shutdown() {
+    keepAliveRunner.shutdown();
+  }
+
 }

graphql-java-servlet/src/main/java/graphql/kickstart/servlet/GraphQLWebsocketServlet.java

@@ -116,6 +116,24 @@ public GraphQLWebsocketServlet(
             .collect(toList());
   }
 
+  public GraphQLWebsocketServlet(
+      GraphQLInvoker graphQLInvoker,
+      GraphQLSubscriptionInvocationInputFactory invocationInputFactory,
+      GraphQLObjectMapper graphQLObjectMapper,
+      List<SubscriptionProtocolFactory> subscriptionProtocolFactory,
+      SubscriptionProtocolFactory fallbackSubscriptionProtocolFactory) {
+
+    this.subscriptionProtocolFactories = subscriptionProtocolFactory;
+    this.fallbackSubscriptionProtocolFactory = fallbackSubscriptionProtocolFactory;
+
+    allSubscriptionProtocols =
+        Stream.concat(
+                subscriptionProtocolFactories.stream(),
+                Stream.of(fallbackSubscriptionProtocolFactory))
+            .map(SubscriptionProtocolFactory::getProtocol)
+            .collect(toList());
+  }
+
   @Override
   public void onOpen(Session session, EndpointConfig endpointConfig) {
     final WebSocketSubscriptionProtocolFactory subscriptionProtocolFactory =
@@ -234,6 +252,12 @@ public void beginShutDown() {
         log.error("GraphQLWebsocketServlet did not shut down cleanly!");
         sessionSubscriptionCache.clear();
       }
+
+      for (SubscriptionProtocolFactory protocolFactory : subscriptionProtocolFactories) {
+        protocolFactory.shutdown();
+      }
+
+      fallbackSubscriptionProtocolFactory.shutdown();
     }
 
     isShutDown.set(true);