diff --git a/compiler/src/main/cpp/capnpc-java.c++ b/compiler/src/main/cpp/capnpc-java.c++
index 54744ae..5226bc4 100644
--- a/compiler/src/main/cpp/capnpc-java.c++
+++ b/compiler/src/main/cpp/capnpc-java.c++
@@ -1137,6 +1137,9 @@ private:
             spaces(indent), "  }\n",
             spaces(indent), "  public void set", titleCase, "(", serverType, " value) {\n",
             spaces(indent), "    this.set", titleCase, "(new ", clientType, "(value));\n",
+            spaces(indent), "  }\n",
+            spaces(indent), "  public void set", titleCase, "(java.util.concurrent.CompletableFuture<? extends ", clientType, "> value) {\n",
+            spaces(indent), "    this.set", titleCase, "(new ", clientType, "(value));\n",
             spaces(indent), "  }\n"
           ),
 
@@ -1825,7 +1828,7 @@ private:
           sp, "    public Client(org.capnproto.ClientHook hook) { super(hook); }\n",
           sp, "    public Client(org.capnproto.Capability.Client cap) { super(cap); }\n",
           sp, "    public Client(Server server) { super(server); }\n",
-          sp, "    public <T extends Client> Client(java.util.concurrent.CompletionStage<T> promise) {\n",
+          sp, "    public Client(java.util.concurrent.CompletionStage<? extends Client> promise) {\n",
           sp, "      super(promise);\n",
           sp, "    }\n",
           sp, "    public static final class Methods {\n",
diff --git a/runtime-rpc/src/test/java/org/capnproto/RpcTest.java b/runtime-rpc/src/test/java/org/capnproto/RpcTest.java
index 4fcbac6..4c8faa9 100644
--- a/runtime-rpc/src/test/java/org/capnproto/RpcTest.java
+++ b/runtime-rpc/src/test/java/org/capnproto/RpcTest.java
@@ -484,7 +484,7 @@ public class RpcTest {
 
         {
             var req = client.holdRequest();
-            req.getParams().setCap(new Test.TestInterface.Client(paf));
+            req.getParams().setCap(paf);
             req.send().join();
         }
 
diff --git a/runtime/src/main/java/org/capnproto/Capability.java b/runtime/src/main/java/org/capnproto/Capability.java
index cfb9f68..75bb986 100644
--- a/runtime/src/main/java/org/capnproto/Capability.java
+++ b/runtime/src/main/java/org/capnproto/Capability.java
@@ -117,9 +117,9 @@ public final class Capability {
             this.hook = hook;
         }
 
-        public <T extends Client> Client(CompletionStage<T> promise) {
+        public Client(CompletionStage<? extends Client> promise) {
             this(Capability.newLocalPromiseClient(
-                    promise.thenApply(client -> client.getHook())));
+                    promise.thenApply(Client::getHook)));
         }
 
         public Client(Throwable exc) {