fix: Address bind address review feedback

- Use bracket notation for IPv6 hosts in startup log
- Add isLoopbackAddress() assertion to loopback bind test
- Remove redundant shouldBindToWildcardWhenBindAddressIsExplicitlyNull test
- Update bindAddress() Javadoc to remove test-intent leak
- Convert loopback test to use HttpClient instead of HttpURLConnection

Author: thced

src/main/java/com/retailsvc/http/OpenApiServer.java

@@ -122,9 +122,11 @@ record HandlerConfig(
 
     this.shutdownTimeoutSeconds = shutdownTimeoutSeconds;
 
+    String host = httpServer.getAddress().getHostString();
+    String displayHost = host.contains(":") ? "[" + host + "]" : host;
     LOG.info(
         "Server started ({}:{}) in {}ms",
-        httpServer.getAddress().getHostString(),
+        displayHost,
         httpServer.getAddress().getPort(),
         System.currentTimeMillis() - t0);
   }
@@ -134,8 +136,8 @@ public int listenPort() {
   }
 
   /**
-   * Returns the actual address the server is bound to, including any wildcard resolution by the
-   * underlying {@link HttpServer}. Useful for verifying loopback restriction.
+   * Returns the local address the server is bound to. For a wildcard-bound server this is the
+   * wildcard address; for a loopback-bound server this is the loopback address.
    */
   public InetAddress bindAddress() {
     return httpServer.getAddress().getAddress();

src/test/java/com/retailsvc/http/OpenApiServerTest.java

@@ -1,6 +1,8 @@
 package com.retailsvc.http;
 
+import static java.net.http.HttpClient.Version.HTTP_1_1;
 import static java.util.Collections.emptyMap;
+import static java.util.concurrent.Executors.newVirtualThreadPerTaskExecutor;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
@@ -10,6 +12,9 @@
 import java.net.HttpURLConnection;
 import java.net.InetAddress;
 import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
 import java.util.List;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
@@ -59,23 +64,28 @@ void testExceptionIsThrownOnInvalidHttpPort() {
   }
 
   @Test
-  void shouldBindOnlyToLoopbackWhenBindAddressIsLoopback() throws IOException {
+  void shouldBindOnlyToLoopbackWhenBindAddressIsLoopback() throws Exception {
     try (var server =
         OpenApiServer.builder()
             .spec(testSpec())
             .handlers(emptyMap())
             .port(0)
             .bindAddress(InetAddress.getLoopbackAddress())
             .build()) {
+      assertThat(server.bindAddress().isLoopbackAddress()).isTrue();
       int port = server.listenPort();
-      HttpURLConnection conn =
-          (HttpURLConnection)
-              URI.create("http://127.0.0.1:" + port + "/api/missing").toURL().openConnection();
-      try {
-        assertThat(conn.getResponseCode()).isEqualTo(HttpURLConnection.HTTP_NOT_FOUND);
-      } finally {
-        conn.disconnect();
-      }
+      HttpClient client =
+          HttpClient.newBuilder()
+              .executor(newVirtualThreadPerTaskExecutor())
+              .version(HTTP_1_1)
+              .build();
+      HttpRequest request =
+          HttpRequest.newBuilder()
+              .uri(URI.create("http://127.0.0.1:" + port + "/api/missing"))
+              .GET()
+              .build();
+      HttpResponse<Void> response = client.send(request, HttpResponse.BodyHandlers.discarding());
+      assertThat(response.statusCode()).isEqualTo(HttpURLConnection.HTTP_NOT_FOUND);
     }
   }
 
@@ -87,19 +97,6 @@ void shouldBindToWildcardWhenBindAddressIsUnset() throws IOException {
     }
   }
 
-  @Test
-  void shouldBindToWildcardWhenBindAddressIsExplicitlyNull() throws IOException {
-    try (var server =
-        OpenApiServer.builder()
-            .spec(testSpec())
-            .handlers(emptyMap())
-            .port(0)
-            .bindAddress(null)
-            .build()) {
-      assertThat(server.bindAddress().isAnyLocalAddress()).isTrue();
-    }
-  }
-
   private Spec testSpec() {
     Map<String, Object> raw =
         Map.of(