Merge pull request #324 from scalecube/fix-minor-issue2

Fix minor issues

Author: artem-v

cluster/src/main/java/io/scalecube/cluster/membership/MembershipProtocolImpl.java

@@ -98,6 +98,7 @@ private enum MembershipUpdateReason {
 
   // Disposables
   private final Disposable.Composite actionsDisposables = Disposables.composite();
+  private final Disposable.Swap disposable = Disposables.swap();
 
   // Scheduled
   private final Scheduler scheduler;
@@ -293,6 +294,7 @@ private void start0(MonoSink<Object> sink) {
   public void stop() {
     // Stop accepting requests, events and sending sync
     actionsDisposables.dispose();
+    disposable.dispose();
 
     // Cancel remove members tasks
     for (String memberId : suspicionTimeoutTasks.keySet()) {
@@ -475,7 +477,7 @@ private Optional<Address> selectSyncAddress() {
 
   private void schedulePeriodicSync() {
     int syncInterval = membershipConfig.syncInterval();
-    actionsDisposables.add(
+    disposable.update(
         scheduler.schedulePeriodically(
             this::doSync, syncInterval, syncInterval, TimeUnit.MILLISECONDS));
   }

transport-parent/transport-api/src/main/java/io/scalecube/cluster/transport/api/Message.java

@@ -222,7 +222,7 @@ public void readExternal(ObjectInput in) throws IOException, ClassNotFoundExcept
     for (int i = 0; i < headersSize; i++) {
       String name = in.readUTF();
       String value = in.readUTF();
-      headers.put(name, value.equals("null") ? null : value);
+      headers.put(name, "null".equals(value) ? null : value);
     }
     this.headers = Collections.unmodifiableMap(headers);
     // data