diff --git a/java-api/src/java11/java/xyz/wagyourtail/jvmdg/j11/impl/http/HttpClientImpl.java b/java-api/src/java11/java/xyz/wagyourtail/jvmdg/j11/impl/http/HttpClientImpl.java
index 66326a4..87b7551 100644
--- a/java-api/src/java11/java/xyz/wagyourtail/jvmdg/j11/impl/http/HttpClientImpl.java
+++ b/java-api/src/java11/java/xyz/wagyourtail/jvmdg/j11/impl/http/HttpClientImpl.java
@@ -13,10 +13,7 @@
 import java.net.*;
 import java.nio.ByteBuffer;
 import java.time.Duration;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
+import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Flow;
@@ -187,7 +184,8 @@ public void onComplete() {
         }
 
         int responseCode = connection.getResponseCode();
-        Map<String, List<String>> headers = connection.getHeaderFields();
+        Map<String, List<String>> headers = new HashMap<>(connection.getHeaderFields());
+        headers.remove(null);
         Version version = J_N_H_HttpClient.Version.HTTP_1_1;
         HttpResponseInfo info = new HttpResponseInfo(responseCode, new J_N_H_HttpHeaders(headers), version);
         J_N_H_HttpResponse.BodySubscriber<T> subscriber = handler.apply(info);