Add examples for Java HttpClient with Basic authentication.

core-java-modules/core-java-11-2/src/main/java/com/baeldung/httpclient/basicauthentication/HttpClientBasicAuthentication.java

@@ -0,0 +1,67 @@
+package com.baeldung.httpclient.basicauthentication;
+
+import java.io.IOException;
+import java.net.Authenticator;
+import java.net.PasswordAuthentication;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.util.Base64;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class HttpClientBasicAuthentication {
+
+    private static final Logger logger = LoggerFactory.getLogger(HttpClientBasicAuthentication.class);
+
+    public static void main(String[] args) throws URISyntaxException, IOException, InterruptedException {
+        useClientWithAuthenticator();
+        useClientWithHeaders();
+    }
+
+    private static void useClientWithAuthenticator() throws URISyntaxException, IOException, InterruptedException {
+        HttpClient client = HttpClient.newBuilder()
+            .authenticator(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication("postman", "password".toCharArray());
+                }
+            })
+            .build();
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .GET()
+            .uri(new URI("https://postman-echo.com/basic-auth"))
+            .build();
+
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+
+        logger.info("Status using authenticator {}", response.statusCode());
+    }
+
+    private static void useClientWithHeaders() throws IOException, InterruptedException, URISyntaxException {
+        HttpClient client = HttpClient.newBuilder()
+            .build();
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .GET()
+            .uri(new URI("https://postman-echo.com/basic-auth"))
+            .header("Authorization", getBasicAuthenticationHeader("postman", "password"))
+            .build();
+
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+
+        logger.info("Status using headers: {}", response.statusCode());
+    }
+
+    private static final String getBasicAuthenticationHeader(String username, String password) {
+        String valueToEncode = username + ":" + password;
+        return "Basic " + Base64.getEncoder()
+            .encodeToString(valueToEncode.getBytes());
+    }
+
+}