refactor: Use HttpURLConnection constants in alive/spec handlers

Author: thced

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

@@ -4,6 +4,7 @@
 import static java.net.HttpURLConnection.HTTP_BAD_REQUEST;
 import static java.net.HttpURLConnection.HTTP_INTERNAL_ERROR;
 import static java.net.HttpURLConnection.HTTP_NOT_FOUND;
+import static java.net.HttpURLConnection.HTTP_NO_CONTENT;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.retailsvc.http.internal.ClasspathResourceHandler;
@@ -61,7 +62,7 @@ public static HttpHandler aliveHandler() {
     return new MethodLimitedHandler(
         exchange -> {
           try (exchange) {
-            exchange.sendResponseHeaders(204, -1);
+            exchange.sendResponseHeaders(HTTP_NO_CONTENT, -1);
           }
         });
   }

src/main/java/com/retailsvc/http/internal/ClasspathResourceHandler.java

@@ -1,5 +1,7 @@
 package com.retailsvc.http.internal;
 
+import static java.net.HttpURLConnection.HTTP_OK;
+
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import java.io.IOException;
@@ -34,10 +36,10 @@ public void handle(HttpExchange exchange) throws IOException {
       exchange.getResponseHeaders().add("Content-Type", contentType);
       if ("HEAD".equals(exchange.getRequestMethod())) {
         exchange.getResponseHeaders().add("Content-Length", String.valueOf(bytes.length));
-        exchange.sendResponseHeaders(200, -1);
+        exchange.sendResponseHeaders(HTTP_OK, -1);
         return;
       }
-      exchange.sendResponseHeaders(200, bytes.length);
+      exchange.sendResponseHeaders(HTTP_OK, bytes.length);
       exchange.getResponseBody().write(bytes);
     }
   }