diff --git a/java/hop/ServerApi.java b/java/hop/ServerApi.java
index 2631af6..bf72c6a 100644
--- a/java/hop/ServerApi.java
+++ b/java/hop/ServerApi.java
@@ -4,12 +4,13 @@
 
 package hop;
 
+import java.io.Flushable;
 import java.io.IOException;
 import java.util.UUID;
 
 /**
  */
-public class ServerApi {
+public class ServerApi implements Flushable {
     public NodeContainer _container;
     public String _serverName;
     public String _kName;
@@ -37,9 +38,13 @@ public class ServerApi {
         _container.post(_serverName, sink, message, null);
     }
 
+    public void flush() throws IOException {
+        _container.flush(_serverName);
+    }
+
     public synchronized Object subscribe(String source, Object filter, String sink, String name) throws InterruptedException, IOException {
         send(source, SexpMessage.subscribe(filter, sink, name, _container.getName(), _kName));
-        _container.flush(_serverName);
+        flush();
         SexpList reply = _nextReply();
         assert reply.getBytes(0).getDataString().equals(SexpMessage._subscribe_ok);
         return reply.get(1);
@@ -55,13 +60,13 @@ public class ServerApi {
 
     public void unsubscribe(String source, Object token) throws IOException {
         send(source, SexpMessage.unsubscribe(token));
-        _container.flush(_serverName);
+        flush();
         /* TODO: optional synchronous reply? */
     }
 
     public synchronized Object create(String nodeClassName, Object arg) throws InterruptedException, IOException {
         send("factory", SexpMessage.create(nodeClassName, arg, _container.getName(), _kName));
-        _container.flush(_serverName);
+        flush();
         SexpList reply = _nextReply();
         SexpBytes selector = reply.getBytes(0);
         if (selector.equals(SexpMessage._create_ok)) return null;
diff --git a/java/hop/Test3.java b/java/hop/Test3.java
index f77749b..63512ef 100644
--- a/java/hop/Test3.java
+++ b/java/hop/Test3.java
@@ -21,6 +21,7 @@ public class Test3 {
         NodeContainer nc = new NodeContainer();
 
         System.out.println("Hostname: " + hostname);
+
         System.out.println("Container: " + nc.getName());
 
         Relay r = new Relay(nc, hostname);
@@ -33,7 +34,7 @@ public class Test3 {
             api.post("q1", null, Integer.toString(i), null);
             count++;
             if ((count % 100000) == 0) {
-                r.flush();
+                api.flush();
                 long now = System.currentTimeMillis();
                 double delta = (now - startTime) / 1000.0;
                 System.out.println("Sent "+count+" messages in "+delta+" seconds, rate = " + (count / delta) + " Hz");
diff --git a/java/hop/TestPingPong.java b/java/hop/TestPingPong.java
index e37dfae..d8de0b6 100644
--- a/java/hop/TestPingPong.java
+++ b/java/hop/TestPingPong.java
@@ -39,6 +39,7 @@ public class TestPingPong {
             Object x = sub.getQueue().take();
             //System.out.println("Message: " + x);
             api.post("rep", "reply", SexpList.with("ok").and(x), null);
+            api.flush();
         }
     }
 
@@ -57,7 +58,8 @@ public class TestPingPong {
         long startTime = System.currentTimeMillis();
         for (int i = 0; i < 100000; i++) {
             api.post("req", "request", Integer.toString(i), null);
-	    sub.getQueue().take();
+            api.flush();
+            sub.getQueue().take();
             int j = i + 1;
             if ((j % 100) == 0) {
                 long now = System.currentTimeMillis();