CR

Author: panchenko

stub/src/main/java/io/grpc/stub/StreamObservers.java

@@ -25,14 +25,15 @@
  * {@link CallStreamObserver}.
  */
 public final class StreamObservers {
+  // Prevent instantiation
+  private StreamObservers() { }
+
   /**
    * Utility method to call {@link StreamObserver#onNext(Object)} and
    * {@link StreamObserver#onCompleted()} on the specified responseObserver.
    */
   @ExperimentalApi("https://github.com/grpc/grpc-java/issues/10957")
   public static <T> void nextAndComplete(StreamObserver<T> responseObserver, T response) {
-    Preconditions.checkNotNull(response, "response");
-
     responseObserver.onNext(response);
     responseObserver.onCompleted();
   }

stub/src/test/java/io/grpc/stub/StreamObserversTest.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2025 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.stub;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.mockito.Mockito;
+
+public class StreamObserversTest {
+
+  @Test
+  public void nextAndComplete() {
+    StreamObserver<String> observer = Mockito.mock(StreamObserver.class);
+    InOrder inOrder = Mockito.inOrder(observer);
+    StreamObservers.nextAndComplete(observer, "TEST");
+    inOrder.verify(observer).onNext("TEST");
+    inOrder.verify(observer).onCompleted();
+    inOrder.verifyNoMoreInteractions();
+  }
+}