diff --git a/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapter.java b/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapter.java
index 7ef88bc6158..e55338ae6e1 100644
--- a/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapter.java
+++ b/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapter.java
@@ -56,6 +56,18 @@
 
 /**
  * A {@link ReactorHttpExchangeAdapter} implementation for the Armeria {@link WebClient}.
+ *
+ * <p><pre>{@code
+ * import com.linecorp.armeria.client.WebClient;
+ * import org.springframework.web.service.invoker.HttpServiceProxyFactory;
+ *
+ * WebClient webClient = ...;
+ * ArmeriaHttpExchangeAdapter adapter = ArmeriaHttpExchangeAdapter.of(webClient);
+ * MyService service =
+ *   HttpServiceProxyFactory.builderFor(adapter)
+ *                          .build()
+ *                          .createClient(MyService.class);
+ * }</pre>
  */
 public final class ArmeriaHttpExchangeAdapter extends AbstractReactorHttpExchangeAdapter {
 
@@ -144,13 +156,13 @@ public boolean supportsRequestAttributes() {
      * Sends the specified {@link HttpRequestValues} to the {@link WebClient} and returns the response.
      *
      * <p><h4>Implementation note</h4>
-     * In order to encode {@link HttpRequestValues#getBodyValue()} to {@link HttpData}, we
-     * need to convert the {@link HttpRequestValues} to {@link ClientRequest} first. The serialization process
-     * is delegated to the {@link ClientRequest}. After that, the request is written to
-     * {@link ArmeriaClientHttpRequest} to send the request via the {@link WebClient}.
+     * In order to encode {@link HttpRequestValues#getBodyValue()} to {@link HttpData}, we need to convert
+     * the {@link HttpRequestValues} to {@link ClientRequest} first. The serialization process is delegated to
+     * the {@link ClientRequest}. After that, the request is written to {@link ArmeriaClientHttpRequest} to send
+     * the request via the {@link WebClient}.
      *
-     * <p>The response handling has to be done in the reverse order. Armeria {@link HttpResponse} is converted into
-     * {@link ArmeriaClientHttpResponse} first and then converted into {@link ClientResponse}.
+     * <p>The response handling has to be done in the reverse order. Armeria {@link HttpResponse} is converted
+     * into {@link ArmeriaClientHttpResponse} first and then converted into {@link ClientResponse}.
      */
     private Mono<ClientResponse> execute(HttpRequestValues requestValues) {
         final URI uri;
diff --git a/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/package-info.java b/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/package-info.java
new file mode 100644
index 00000000000..6535d480e07
--- /dev/null
+++ b/spring/spring6/src/main/java/com/linecorp/armeria/spring/client/package-info.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2016 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you 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:
+ *
+ *   https://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.
+ */
+
+/**
+ * <a href="https://docs.spring.io/spring-framework/reference/integration/rest-clients.html#rest-http-interface">
+ * Spring 6 HTTP interface</a> integration.
+ */
+@NonNullByDefault
+package com.linecorp.armeria.spring.client;
+
+import com.linecorp.armeria.common.annotation.NonNullByDefault;
diff --git a/spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/client/package-info.java b/spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/client/package-info.java
new file mode 100644
index 00000000000..ba3539a8598
--- /dev/null
+++ b/spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/client/package-info.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2016 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you 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:
+ *
+ *   https://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.
+ */
+
+/**
+ * Various classes used internally. Anything in this package can be changed or removed at any time.
+ */
+@NonNullByDefault
+package com.linecorp.armeria.spring.internal.client;
+
+import com.linecorp.armeria.common.annotation.NonNullByDefault;
diff --git a/spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/common/package-info.java b/spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/common/package-info.java
new file mode 100644
index 00000000000..f5f9f0a729f
--- /dev/null
+++ b/spring/spring6/src/main/java/com/linecorp/armeria/spring/internal/common/package-info.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2016 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you 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:
+ *
+ *   https://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.
+ */
+
+/**
+ * Various classes used internally. Anything in this package can be changed or removed at any time.
+ */
+@NonNullByDefault
+package com.linecorp.armeria.spring.internal.common;
+
+import com.linecorp.armeria.common.annotation.NonNullByDefault;
diff --git a/spring/spring6/src/test/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapterTest.java b/spring/spring6/src/test/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapterTest.java
index 8250c6aa6a8..47d5dbc81f1 100644
--- a/spring/spring6/src/test/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapterTest.java
+++ b/spring/spring6/src/test/java/com/linecorp/armeria/spring/client/ArmeriaHttpExchangeAdapterTest.java
@@ -29,7 +29,6 @@
  * limitations under the License.
  */
 
-
 package com.linecorp.armeria.spring.client;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -184,13 +183,13 @@ void uriBuilderFactoryWithPathVariableAndRequestParam() throws Exception {
         assertThat(server.takeRequest(1, TimeUnit.SECONDS)).isNull();
     }
 
-
     @Test
     void ignoredUriBuilderFactory() throws Exception {
         final String expectedResponseBody = "hello";
         prepareResponse(response -> response.status(200).content(expectedResponseBody));
         final URI dynamicUri = server.httpUri().resolve("/greeting/123");
-        final UriBuilderFactory factory = new DefaultUriBuilderFactory(anotherServer.httpUri().resolve("/").toString());
+        final UriBuilderFactory factory = new DefaultUriBuilderFactory(
+                anotherServer.httpUri().resolve("/").toString());
 
         final String actualBody = initService().getWithIgnoredUriBuilderFactory(dynamicUri, factory);
 
@@ -246,6 +245,5 @@ String getWithUriBuilderFactory(UriBuilderFactory uriBuilderFactory,
 
         @GetExchange("/greeting")
         String getWithIgnoredUriBuilderFactory(URI uri, UriBuilderFactory uriBuilderFactory);
-
     }
 }