Fixed checkStyle and ErrorProne warns

broker/src/main/java/io/moquette/spi/InboundFlightZone.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2012-2017 The original author or authors
+ * ------------------------------------------------------
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Apache License v2.0 which accompanies this distribution.
+ *
+ * The Eclipse Public License is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * The Apache License v2.0 is available at
+ * http://www.opensource.org/licenses/apache2.0.php
+ *
+ * You may elect to redistribute this code under either of these licenses.
+ */
+package io.moquette.spi;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+class InboundFlightZone {
+
+    private final Map<Integer, IMessagesStore.StoredMessage> inboundFlightMessages = new ConcurrentHashMap<>();
+
+    IMessagesStore.StoredMessage lookup(int messageID) {
+        return inboundFlightMessages.get(messageID);
+    }
+
+    void waitingRel(int messageID, IMessagesStore.StoredMessage msg) {
+        inboundFlightMessages.put(messageID, msg);
+    }
+}