diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/NodeStats.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/NodeStats.java
index b227557ff9e..a21c99b68e2 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/NodeStats.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/NodeStats.java
@@ -211,18 +211,10 @@ public class NodeStats extends BaseNodeResponse implements ToXContent {
         if (in.readBoolean()) {
             indices = NodeIndicesStats.readIndicesStats(in);
         }
-        if (in.readBoolean()) {
-            os = new OsStats(in);
-        }
-        if (in.readBoolean()) {
-            process = new ProcessStats(in);
-        }
-        if (in.readBoolean()) {
-            jvm = new JvmStats(in);
-        }
-        if (in.readBoolean()) {
-            threadPool = ThreadPoolStats.readThreadPoolStats(in);
-        }
+        os = in.readOptionalWriteable(OsStats::new);
+        process = in.readOptionalWriteable(ProcessStats::new);
+        jvm = in.readOptionalWriteable(JvmStats::new);
+        threadPool = in.readOptionalWriteable(ThreadPoolStats::new);
         if (in.readBoolean()) {
             fs = new FsInfo(in);
         }
@@ -248,30 +240,10 @@ public class NodeStats extends BaseNodeResponse implements ToXContent {
             out.writeBoolean(true);
             indices.writeTo(out);
         }
-        if (os == null) {
-            out.writeBoolean(false);
-        } else {
-            out.writeBoolean(true);
-            os.writeTo(out);
-        }
-        if (process == null) {
-            out.writeBoolean(false);
-        } else {
-            out.writeBoolean(true);
-            process.writeTo(out);
-        }
-        if (jvm == null) {
-            out.writeBoolean(false);
-        } else {
-            out.writeBoolean(true);
-            jvm.writeTo(out);
-        }
-        if (threadPool == null) {
-            out.writeBoolean(false);
-        } else {
-            out.writeBoolean(true);
-            threadPool.writeTo(out);
-        }
+        out.writeOptionalWriteable(os);
+        out.writeOptionalWriteable(process);
+        out.writeOptionalWriteable(jvm);
+        out.writeOptionalWriteable(threadPool);
         if (fs == null) {
             out.writeBoolean(false);
         } else {
diff --git a/core/src/main/java/org/elasticsearch/threadpool/ThreadPoolStats.java b/core/src/main/java/org/elasticsearch/threadpool/ThreadPoolStats.java
index fdbbaef19d6..ead076fc83b 100644
--- a/core/src/main/java/org/elasticsearch/threadpool/ThreadPoolStats.java
+++ b/core/src/main/java/org/elasticsearch/threadpool/ThreadPoolStats.java
@@ -21,33 +21,26 @@ package org.elasticsearch.threadpool;
 
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.io.stream.Streamable;
+import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
-/**
- */
-public class ThreadPoolStats implements Streamable, ToXContent, Iterable<ThreadPoolStats.Stats> {
+public class ThreadPoolStats implements Writeable, ToXContent, Iterable<ThreadPoolStats.Stats> {
 
-    public static class Stats implements Streamable, ToXContent, Comparable<Stats> {
+    public static class Stats implements Writeable, ToXContent, Comparable<Stats> {
 
-        private String name;
-        private int threads;
-        private int queue;
-        private int active;
-        private long rejected;
-        private int largest;
-        private long completed;
-
-        Stats() {
-
-        }
+        private final String name;
+        private final int threads;
+        private final int queue;
+        private final int active;
+        private final long rejected;
+        private final int largest;
+        private final long completed;
 
         public Stats(String name, int threads, int queue, int active, long rejected, int largest, long completed) {
             this.name = name;
@@ -59,6 +52,27 @@ public class ThreadPoolStats implements Streamable, ToXContent, Iterable<ThreadP
             this.completed = completed;
         }
 
+        public Stats(StreamInput in) throws IOException {
+            name = in.readString();
+            threads = in.readInt();
+            queue = in.readInt();
+            active = in.readInt();
+            rejected = in.readLong();
+            largest = in.readInt();
+            completed = in.readLong();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(name);
+            out.writeInt(threads);
+            out.writeInt(queue);
+            out.writeInt(active);
+            out.writeLong(rejected);
+            out.writeInt(largest);
+            out.writeLong(completed);
+        }
+
         public String getName() {
             return this.name;
         }
@@ -87,28 +101,6 @@ public class ThreadPoolStats implements Streamable, ToXContent, Iterable<ThreadP
             return this.completed;
         }
 
-        @Override
-        public void readFrom(StreamInput in) throws IOException {
-            name = in.readString();
-            threads = in.readInt();
-            queue = in.readInt();
-            active = in.readInt();
-            rejected = in.readLong();
-            largest = in.readInt();
-            completed = in.readLong();
-        }
-
-        @Override
-        public void writeTo(StreamOutput out) throws IOException {
-            out.writeString(name);
-            out.writeInt(threads);
-            out.writeInt(queue);
-            out.writeInt(active);
-            out.writeLong(rejected);
-            out.writeInt(largest);
-            out.writeLong(completed);
-        }
-
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.startObject(name);
@@ -154,43 +146,23 @@ public class ThreadPoolStats implements Streamable, ToXContent, Iterable<ThreadP
 
     private List<Stats> stats;
 
-    ThreadPoolStats() {
-
-    }
-
     public ThreadPoolStats(List<Stats> stats) {
         Collections.sort(stats);
         this.stats = stats;
     }
 
-    @Override
-    public Iterator<Stats> iterator() {
-        return stats.iterator();
-    }
-
-    public static ThreadPoolStats readThreadPoolStats(StreamInput in) throws IOException {
-        ThreadPoolStats stats = new ThreadPoolStats();
-        stats.readFrom(in);
-        return stats;
-    }
-
-    @Override
-    public void readFrom(StreamInput in) throws IOException {
-        int size = in.readVInt();
-        stats = new ArrayList<>(size);
-        for (int i = 0; i < size; i++) {
-            Stats stats1 = new Stats();
-            stats1.readFrom(in);
-            stats.add(stats1);
-        }
+    public ThreadPoolStats(StreamInput in) throws IOException {
+        stats = in.readList(Stats::new);
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeVInt(stats.size());
-        for (Stats stat : stats) {
-            stat.writeTo(out);
-        }
+        out.writeList(stats);
+    }
+
+    @Override
+    public Iterator<Stats> iterator() {
+        return stats.iterator();
     }
 
     static final class Fields {