diff --git a/jaeger-core/src/main/java/com/uber/jaeger/senders/HttpSender.java b/jaeger-core/src/main/java/com/uber/jaeger/senders/HttpSender.java
index 289ab80c2..d50868e86 100644
--- a/jaeger-core/src/main/java/com/uber/jaeger/senders/HttpSender.java
+++ b/jaeger-core/src/main/java/com/uber/jaeger/senders/HttpSender.java
@@ -36,15 +36,13 @@
 import org.apache.thrift.TException;
 import org.apache.thrift.TSerializer;
 import org.apache.thrift.protocol.TBinaryProtocol;
-import org.apache.thrift.protocol.TProtocolFactory;
 
 public class HttpSender extends ThriftSender {
 
   private static final String HTTP_COLLECTOR_JAEGER_THRIFT_FORMAT_PARAM = "format=jaeger.thrift";
-  private static final TProtocolFactory PROTOCOL_FACTORY = new TBinaryProtocol.Factory();
-  private static final TSerializer SERIALIZER = new TSerializer(PROTOCOL_FACTORY);
   private static final int ONE_MB_IN_BYTES = 1048576;
   private static final MediaType MEDIA_TYPE_THRIFT = MediaType.parse("application/x-thrift");
+  private final TSerializer serializer;
   private final OkHttpClient httpClient;
   private final Request.Builder requestBuilder;
 
@@ -75,7 +73,7 @@ public HttpSender(String endpoint, int maxPayloadBytes) {
    * @param client a client used to make http requests
    */
   private HttpSender(String endpoint, int maxPayloadBytes, OkHttpClient client) {
-    super(PROTOCOL_FACTORY, maxPayloadBytes);
+    super(new TBinaryProtocol.Factory(), maxPayloadBytes);
     HttpUrl collectorUrl = HttpUrl
         .parse(String.format("%s?%s", endpoint, HTTP_COLLECTOR_JAEGER_THRIFT_FORMAT_PARAM));
     if (collectorUrl == null) {
@@ -83,12 +81,13 @@ private HttpSender(String endpoint, int maxPayloadBytes, OkHttpClient client) {
     }
     this.httpClient = client;
     this.requestBuilder = new Request.Builder().url(collectorUrl);
+    this.serializer = new TSerializer(protocolFactory);
   }
 
   @Override
   public void send(Process process, List<Span> spans) throws TException {
     Batch batch = new Batch(process, spans);
-    byte[] bytes = SERIALIZER.serialize(batch);
+    byte[] bytes = serializer.serialize(batch);
 
     RequestBody body = RequestBody.create(MEDIA_TYPE_THRIFT, bytes);
     Request request = requestBuilder.post(body).build();
diff --git a/jaeger-core/src/main/java/com/uber/jaeger/senders/ThriftSender.java b/jaeger-core/src/main/java/com/uber/jaeger/senders/ThriftSender.java
index 55c34b658..d20fa037c 100644
--- a/jaeger-core/src/main/java/com/uber/jaeger/senders/ThriftSender.java
+++ b/jaeger-core/src/main/java/com/uber/jaeger/senders/ThriftSender.java
@@ -45,7 +45,7 @@ public abstract class ThriftSender implements Sender {
   private int byteBufferSize;
   private AutoExpandingBufferWriteTransport memoryTransport;
 
-  private final TProtocolFactory protocolFactory;
+  protected final TProtocolFactory protocolFactory;
   private final int maxSpanBytes;
 
   public ThriftSender(TProtocolFactory protocolFactory, int maxPacketSize) {
diff --git a/jaeger-core/src/main/java/com/uber/jaeger/senders/UdpSender.java b/jaeger-core/src/main/java/com/uber/jaeger/senders/UdpSender.java
index 5fd22f10b..23da30b6f 100644
--- a/jaeger-core/src/main/java/com/uber/jaeger/senders/UdpSender.java
+++ b/jaeger-core/src/main/java/com/uber/jaeger/senders/UdpSender.java
@@ -31,11 +31,9 @@
 import lombok.ToString;
 import org.apache.thrift.TException;
 import org.apache.thrift.protocol.TCompactProtocol;
-import org.apache.thrift.protocol.TProtocolFactory;
 
 @ToString(exclude = {"agentClient"})
 public class UdpSender extends ThriftSender {
-  private static final TProtocolFactory PROTOCOL_FACTORY = new TCompactProtocol.Factory();
   public static final String DEFAULT_AGENT_UDP_HOST = "localhost";
   public static final int DEFAULT_AGENT_UDP_COMPACT_PORT = 6831;
 
@@ -43,7 +41,7 @@ public class UdpSender extends ThriftSender {
   private ThriftUdpTransport udpTransport;
 
   public UdpSender(String host, int port, int maxPacketSize) {
-    super(PROTOCOL_FACTORY, maxPacketSize);
+    super(new TCompactProtocol.Factory(), maxPacketSize);
 
     if (host == null || host.length() == 0) {
       host = DEFAULT_AGENT_UDP_HOST;
@@ -54,7 +52,7 @@ public UdpSender(String host, int port, int maxPacketSize) {
     }
 
     udpTransport = ThriftUdpTransport.newThriftUdpClient(host, port);
-    agentClient = new Agent.Client(PROTOCOL_FACTORY.getProtocol(udpTransport));
+    agentClient = new Agent.Client(protocolFactory.getProtocol(udpTransport));
   }
 
   @Override