diff --git a/authz/client/pom.xml b/authz/client/pom.xml
index bf3f6b87d0..a07c7b1ee6 100644
--- a/authz/client/pom.xml
+++ b/authz/client/pom.xml
@@ -63,6 +63,14 @@
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+		    <source>${maven.compiler.source}</source>
+		    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
             <!-- Adding OSGI metadata to the JAR without changing the packaging type. -->
             <plugin>
                 <artifactId>maven-jar-plugin</artifactId>
@@ -98,4 +106,4 @@
         </plugins>
     </build>
 
-</project>
\ No newline at end of file
+</project>
diff --git a/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethod.java b/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethod.java
index be83987750..d132620bac 100644
--- a/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethod.java
+++ b/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethod.java
@@ -48,7 +48,7 @@ public class HttpMethod<R> {
     private HttpMethodResponse<R> response;
 
     public HttpMethod(Configuration configuration, RequestBuilder builder) {
-        this(configuration, builder, new HashMap<>(), new HashMap<>());
+        this(configuration, builder, new HashMap<String, String>(), new HashMap<String, String>());
     }
 
     public HttpMethod(Configuration configuration, RequestBuilder builder, HashMap<String, String> params, HashMap<String, String> headers) {
@@ -155,4 +155,4 @@ public class HttpMethod<R> {
             }
         };
     }
-}
\ No newline at end of file
+}
diff --git a/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethodResponse.java b/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethodResponse.java
index 4155240f7a..fceca19d61 100644
--- a/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethodResponse.java
+++ b/authz/client/src/main/java/org/keycloak/authorization/client/util/HttpMethodResponse.java
@@ -41,7 +41,7 @@ public class HttpMethodResponse<R> {
         });
     }
 
-    public HttpMethodResponse<R> json(Class<R> responseType) {
+    public HttpMethodResponse<R> json(final Class<R> responseType) {
         return new HttpMethodResponse<R>(this.method) {
             @Override
             public R execute() {