[java] deprecate the 'native' methods inside the HttpClient interface (#17340)

Author: joerg1985

java/AGENTS.md

@@ -12,6 +12,9 @@
 See `java/TESTING.md`
 
 ## Code conventions
+### Interfaces
+- New methods added to existing interfaces must provide a default implementation, if possible.
+- Interfaces must not expose the native classes of their implementations.
 
 ### Logging
 ```java

java/src/org/openqa/selenium/remote/http/HttpClient.java

@@ -46,7 +46,9 @@ default void close() {}
    * @param request the HTTP request to send
    * @param handler the BodyHandler that determines how to handle the response body
    * @return a CompletableFuture containing the HTTP response
+   * @deprecated use JdkHttpClient#httpClient() instead.
    */
+  @Deprecated(forRemoval = true)
   <T> CompletableFuture<java.net.http.HttpResponse<T>> sendAsyncNative(
       java.net.http.HttpRequest request, java.net.http.HttpResponse.BodyHandler<T> handler);
 
@@ -59,7 +61,9 @@ <T> CompletableFuture<java.net.http.HttpResponse<T>> sendAsyncNative(
    * @return the HTTP response
    * @throws java.io.IOException if an I/O error occurs
    * @throws InterruptedException if the operation is interrupted
+   * @deprecated use JdkHttpClient#httpClient() instead.
    */
+  @Deprecated(forRemoval = true)
   <T> java.net.http.HttpResponse<T> sendNative(
       java.net.http.HttpRequest request, java.net.http.HttpResponse.BodyHandler<T> handler)
       throws java.io.IOException, InterruptedException;

java/src/org/openqa/selenium/remote/http/jdk/JdkHttpClient.java

@@ -158,6 +158,11 @@ protected PasswordAuthentication getPasswordAuthentication() {
     this.client = builder.build();
   }
 
+  /** Will expose the underlying native HttpClient used. */
+  public java.net.http.HttpClient client() {
+    return client;
+  }
+
   @Override
   public WebSocket openSocket(HttpRequest request, WebSocket.Listener listener) {
     URI uri;