diff --git a/spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/connection/HelloWorldInterceptor.java b/spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/connection/HelloWorldInterceptor.java
index 3760daada7..6ced05cf8c 100644
--- a/spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/connection/HelloWorldInterceptor.java
+++ b/spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/connection/HelloWorldInterceptor.java
@@ -61,36 +61,45 @@ public class HelloWorldInterceptor extends TcpConnectionInterceptorSupport {
 	@Override
 	public boolean onMessage(Message<?> message) {
 		if (!this.negotiated) {
-			Object payload = message.getPayload();
-			if (this.isServer()) {
-				if (payload.equals(hello)) {
-					try {
-						logger.debug(this.toString() + " sending " + this.world);
-						super.send(MessageBuilder.withPayload(world).build());
-						this.negotiated = true;
-						return true;
-					} catch (Exception e) {
-						throw new MessagingException("Negotiation error", e);
+			synchronized(this) {
+				if (!this.negotiated) {
+					Object payload = message.getPayload();
+					logger.debug(this.toString() + " received " + payload);
+					if (this.isServer()) {
+						if (payload.equals(hello)) {
+							try {
+								logger.debug(this.toString() + " sending " + this.world);
+								super.send(MessageBuilder.withPayload(world).build());
+								this.negotiated = true;
+								return true;
+							}
+							catch (Exception e) {
+								throw new MessagingException("Negotiation error", e);
+							}
+						}
+						else {
+							throw new MessagingException("Negotiation error, expected '" + hello +
+									     "' received '" + payload + "'");
+						}
+					}
+					else {
+						if (payload.equals(world)) {
+							this.negotiated = true;
+							this.negotiationSemaphore.release();
+						}
+						else {
+							throw new MessagingException("Negotiation error - expected '" + world +
+										"' received " + payload);
+						}
+						return true;
 					}
-				} else {
-					throw new MessagingException("Negotiation error, expected '" + hello +
-							     "' received '" + payload + "'");
 				}
-			} else {
-				logger.debug(this.toString() + " received " + payload);
-				if (payload.equals(world)) {
-					this.negotiated = true;
-					this.negotiationSemaphore.release();
-				} else {
-					throw new MessagingException("Negotiation error - expected '" + world +
-								"' received " + payload);
-				}
-				return true;
 			}
 		}
 		try {
 			return super.onMessage(message);
-		} finally {
+		}
+		finally {
 			// on the server side, we don't want to close if we are expecting a response
 			if (!(this.isServer() && this.hasRealSender()) && !this.pendingSend) {
 				this.checkDeferredClose();
@@ -113,7 +122,8 @@ public class HelloWorldInterceptor extends TcpConnectionInterceptorSupport {
 				}
 			}
 			super.send(message);
-		} finally {
+		}
+		finally {
 			this.pendingSend = false;
 			this.checkDeferredClose();
 		}