diff --git a/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpExchangeDelegate.java b/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpExchangeDelegate.java
index 33d0f68869f..48de184c007 100644
--- a/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpExchangeDelegate.java
+++ b/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpExchangeDelegate.java
@@ -209,8 +209,11 @@ public class JettyHttpExchangeDelegate extends HttpExchange
     @Override
     public void setStreams(InputStream i, OutputStream o)
     {
-        _is = i;
-        _os = o;
+        assert _is != null;
+        if (i != null)
+            _is = i;
+        if (o != null)
+            _os = o;
     }
 
     @Override