Add HttpClient

src/main/java/step1/Main.java

@@ -1,7 +1,29 @@
 package step1;
 
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.Base64;
+
 public class Main {
     public static void main(String[] args){
-        System.out.println("Hello World");
+
+        try(HttpClient client = HttpClient.newHttpClient()){
+            String msg = "Hello !";
+            byte[] encodedMsg = Base64.getEncoder().encode(msg.getBytes());
+            HttpRequest request = HttpRequest.newBuilder()
+                    .uri(URI.create("http://127.0.0.1:8888"))
+                    .POST(HttpRequest.BodyPublishers.ofByteArray(encodedMsg))
+                    .build();
+
+            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
+
+            System.out.println("Status code: " + response.statusCode());
+            System.out.println("Response body: " + response.body());
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
     }
 }