Fix coverity issues

Change-Id: I7707a42321df2c73e5414926d4000f8672ecfaf3
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>

vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/JVppRegistryImpl.java

@@ -108,12 +108,12 @@ public final class JVppRegistryImpl implements JVppRegistry, ControlPingCallback
         final ControlPingCallback callback;
         synchronized (pingCalls) {
             callback = pingCalls.remove(reply.context);
-        }
             if (callback == null) {
                 LOG.log(Level.WARNING, "No callback was registered for reply context=" + reply.context + " Contexts waiting="
                     + pingCalls.keySet());
                 return;
             }
+        }
         // pass the reply to the callback registered by the ping caller
         callback.onControlPingReply(reply);
     }

vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/future/AbstractFutureJVppInvoker.java

@@ -51,8 +51,10 @@ public abstract class AbstractFutureJVppInvoker implements FutureJVppInvoker {
         this.requests = Objects.requireNonNull(requestMap, "Null requestMap");
     }
 
-    protected synchronized final Map<Integer, CompletableFuture<? extends JVppReply<?>>> getRequests() {
-        return this.requests;
+    protected final Map<Integer, CompletableFuture<? extends JVppReply<?>>> getRequests() {
+        synchronized (requests) {
+            return requests;
+        }
     }
 
     // TODO use Optional in Future, java8