Backward compatibility with java17 (#1956)

* Backward compatibility with java17

* Fix linter

* Test compatibility with java17

* Test compatibility with java17

* Test compatibility with java17

* Add info about supporting java17

Author: faderskd

hermes-client/build.gradle

@@ -2,6 +2,13 @@ plugins {
     id 'java-library'
 }
 
+java {
+    // We need to support Java 17 until all of our clients migrate to Java 21.
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(17)
+    }
+}
+
 dependencies {
     compileOnly group: 'io.micrometer', name: 'micrometer-core', version: versions.micrometer_metrics
     compileOnly group: 'org.glassfish.jersey.core', name: 'jersey-client', version: versions.jersey

hermes-client/src/main/java/pl/allegro/tech/hermes/client/restclient/RestClientHermesSender.java

@@ -1,65 +1,73 @@
 package pl.allegro.tech.hermes.client.restclient;
 
-import org.springframework.web.client.RestClient;
-import pl.allegro.tech.hermes.client.HermesMessage;
-import pl.allegro.tech.hermes.client.HermesResponse;
-import pl.allegro.tech.hermes.client.HermesSender;
+import static java.util.stream.Collectors.toMap;
+import static pl.allegro.tech.hermes.client.HermesResponseBuilder.hermesResponse;
 
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.TreeMap;
 import java.util.concurrent.CompletableFuture;
-
-import static java.util.stream.Collectors.toMap;
-import static pl.allegro.tech.hermes.client.HermesResponseBuilder.hermesResponse;
-
+import org.springframework.web.client.RestClient;
+import pl.allegro.tech.hermes.client.HermesMessage;
+import pl.allegro.tech.hermes.client.HermesResponse;
+import pl.allegro.tech.hermes.client.HermesSender;
 
 public class RestClientHermesSender implements HermesSender {
 
-    private final RestClient restClient;
-
+  private final RestClient restClient;
 
-    public RestClientHermesSender(RestClient restClient) {
-        this.restClient = restClient;
-    }
+  public RestClientHermesSender(RestClient restClient) {
+    this.restClient = restClient;
+  }
 
-    @Override
-    public CompletableFuture<HermesResponse> send(URI uri, HermesMessage message) {
-        CompletableFuture<HermesResponse> future = new CompletableFuture<>();
+  @Override
+  public CompletableFuture<HermesResponse> send(URI uri, HermesMessage message) {
+    CompletableFuture<HermesResponse> future = new CompletableFuture<>();
 
-        var received = restClient
-                .post()
-                .uri(uri)
-                .headers(httpHeaders -> httpHeaders.setAll(message.getHeaders()))
-                .body(message.getBody())
-                .exchange((request, response) -> {
-                    if (response.getStatusCode().is2xxSuccessful()) {
-                        return hermesResponse(message)
-                                .withBody(new String(response.getBody().readAllBytes(), StandardCharsets.UTF_8))
-                                .withHttpStatus(response.getStatusCode().value())
-                                .withHeaderSupplier(header -> convertToCaseInsensitiveMap(response.getHeaders().toSingleValueMap()).get(header))
-                                .build();
-                    } else {
-                        return hermesResponse(message)
-                                .withBody("")
-                                .withHttpStatus(response.getStatusCode().value())
-                                .withHeaderSupplier(header -> convertToCaseInsensitiveMap(response.getHeaders().toSingleValueMap()).get(header))
-                                .build();
-                    }
+    var received =
+        restClient
+            .post()
+            .uri(uri)
+            .headers(httpHeaders -> httpHeaders.setAll(message.getHeaders()))
+            .body(message.getBody())
+            .exchange(
+                (request, response) -> {
+                  if (response.getStatusCode().is2xxSuccessful()) {
+                    return hermesResponse(message)
+                        .withBody(
+                            new String(response.getBody().readAllBytes(), StandardCharsets.UTF_8))
+                        .withHttpStatus(response.getStatusCode().value())
+                        .withHeaderSupplier(
+                            header ->
+                                convertToCaseInsensitiveMap(
+                                        response.getHeaders().toSingleValueMap())
+                                    .get(header))
+                        .build();
+                  } else {
+                    return hermesResponse(message)
+                        .withBody("")
+                        .withHttpStatus(response.getStatusCode().value())
+                        .withHeaderSupplier(
+                            header ->
+                                convertToCaseInsensitiveMap(
+                                        response.getHeaders().toSingleValueMap())
+                                    .get(header))
+                        .build();
+                  }
                 });
 
-        future.complete(received);
-        return future;
-    }
+    future.complete(received);
+    return future;
+  }
 
-    private TreeMap<String, String> convertToCaseInsensitiveMap(Map<String, String> hashMap) {
-        return hashMap.entrySet().stream()
-                .collect(toMap(
-                        Map.Entry::getKey,
-                        Map.Entry::getValue,
-                        (oldVal, newVal) -> newVal,
-                        () -> new TreeMap<>(String.CASE_INSENSITIVE_ORDER)
-                ));
-    }
+  private TreeMap<String, String> convertToCaseInsensitiveMap(Map<String, String> hashMap) {
+    return hashMap.entrySet().stream()
+        .collect(
+            toMap(
+                Map.Entry::getKey,
+                Map.Entry::getValue,
+                (oldVal, newVal) -> newVal,
+                () -> new TreeMap<>(String.CASE_INSENSITIVE_ORDER)));
+  }
 }