diff --git a/pom.xml b/pom.xml
index b856945f3b1e..dcd7fcaccc47 100644
--- a/pom.xml
+++ b/pom.xml
@@ -25,482 +25,483 @@
     THE SOFTWARE.
 
 -->
-  <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <modelVersion>4.0.0</modelVersion>
-  <groupId>com.iluwatar</groupId>
-  <artifactId>java-design-patterns</artifactId>
-  <version>1.26.0-SNAPSHOT</version>
-  <packaging>pom</packaging>
-  <inceptionYear>2014-2022</inceptionYear>
-  <name>Java Design Patterns</name>
-  <description>Java Design Patterns</description>
-  <properties>
-    <!-- General properties -->
-    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.26.0-SNAPSHOT</version>
+    <packaging>pom</packaging>
+    <inceptionYear>2014-2022</inceptionYear>
+    <name>Java Design Patterns</name>
+    <description>Java Design Patterns</description>
+    <properties>
+        <!-- General properties -->
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-    <!-- Spring Boot related dependencies. Keep these in sync! -->
-    <spring-boot.version>3.4.5</spring-boot.version>
-    <junit.version>5.11.4</junit.version>
-    <mockito.version>5.14.2</mockito.version>
-    <logback.version>1.5.34</logback.version>
-    <slf4j.version>2.0.18</slf4j.version>
+        <!-- Spring Boot related dependencies. Keep these in sync! -->
+        <spring-boot.version>3.4.5</spring-boot.version>
+        <junit.version>5.11.4</junit.version>
+        <mockito.version>5.14.2</mockito.version>
+        <logback.version>1.5.34</logback.version>
+        <slf4j.version>2.0.18</slf4j.version>
 
-    <!-- Other dependencies -->
-    <jacoco.version>0.8.13</jacoco.version>
-    <commons-dbcp.version>1.4</commons-dbcp.version>
-    <htmlunit.version>4.17.0</htmlunit.version>
-    <gson.version>2.11.0</gson.version>
-    <guice.version>6.0.0</guice.version>
-    <system-lambda.version>1.1.0</system-lambda.version>
-    <lombok.version>1.18.38</lombok.version>
-    <mongo.version>5.4.0</mongo.version>
-    <bson.version>5.4.0</bson.version>
-    <h2.version>2.3.232</h2.version>
+        <!-- Other dependencies -->
+        <jacoco.version>0.8.13</jacoco.version>
+        <commons-dbcp.version>1.4</commons-dbcp.version>
+        <htmlunit.version>4.17.0</htmlunit.version>
+        <gson.version>2.11.0</gson.version>
+        <guice.version>6.0.0</guice.version>
+        <system-lambda.version>1.1.0</system-lambda.version>
+        <lombok.version>1.18.38</lombok.version>
+        <mongo.version>5.4.0</mongo.version>
+        <bson.version>5.4.0</bson.version>
+        <h2.version>2.3.232</h2.version>
 
-    <!-- Plugins -->
-    <maven-surefire-plugin.version>3.5.2</maven-surefire-plugin.version>
-    <license-maven-plugin.version>5.0.0</license-maven-plugin.version>
-    <maven-compiler-plugin.version>3.14.0</maven-compiler-plugin.version>
+        <!-- Plugins -->
+        <maven-surefire-plugin.version>3.5.2</maven-surefire-plugin.version>
+        <license-maven-plugin.version>5.0.0</license-maven-plugin.version>
+        <maven-compiler-plugin.version>3.14.0</maven-compiler-plugin.version>
 
-    <!-- SonarCloud -->
-    <sonar-maven-plugin.version>5.1.0.4751</sonar-maven-plugin.version>
-    <sonar.host.url>https://sonarcloud.io</sonar.host.url>
-    <sonar.organization>iluwatar</sonar.organization>
-    <sonar.projectKey>iluwatar_java-design-patterns</sonar.projectKey>
-    <sonar.moduleKey>${project.artifactId}</sonar.moduleKey>
-    <sonar.projectName>Java Design Patterns</sonar.projectName>
-  </properties>
-  <modules>
-    <module>abstract-document</module>
-    <module>abstract-factory</module>
-    <module>active-object</module>
-    <module>acyclic-visitor</module>
-    <module>adapter</module>
-    <module>ambassador</module>
-    <module>anti-corruption-layer</module>
-    <module>arrange-act-assert</module>
-    <module>async-method-invocation</module>
-    <module>balking</module>
-    <module>bloc</module>
-    <module>bridge</module>
-    <module>builder</module>
-    <module>business-delegate</module>
-    <module>bytecode</module>
-    <module>caching</module>
-    <module>callback</module>
-    <module>chain-of-responsibility</module>
-    <module>circuit-breaker</module>
-    <module>clean-architecture</module>
-    <module>client-session</module>
-    <module>collecting-parameter</module>
-    <module>collection-pipeline</module>
-    <module>combinator</module>
-    <module>command</module>
-    <module>command-query-responsibility-segregation</module>
-    <module>commander</module>
-    <module>component</module>
-    <module>composite</module>
-    <module>composite-entity</module>
-    <module>composite-view</module>
-    <module>context-object</module>
-    <module>converter</module>
-    <module>curiously-recurring-template-pattern</module>
-    <module>currying</module>
-      <module>dao-factory</module>
-    <module>data-access-object</module>
-    <module>data-bus</module>
-    <module>data-locality</module>
-    <module>data-mapper</module>
-    <module>data-transfer-object</module>
-    <module>decorator</module>
-    <module>delegation</module>
-    <module>dependency-injection</module>
-    <module>dirty-flag</module>
-    <module>domain-model</module>
-    <module>double-buffer</module>
-    <module>double-checked-locking</module>
-    <module>double-dispatch</module>
-    <module>dynamic-proxy</module>
-    <module>event-aggregator</module>
-    <module>event-based-asynchronous</module>
-    <module>event-driven-architecture</module>
-    <module>event-queue</module>
-    <module>event-sourcing</module>
-    <module>execute-around</module>
-    <module>extension-objects</module>
-    <module>facade</module>
-    <module>factory</module>
-    <module>factory-kit</module>
-    <module>factory-method</module>
-    <module>fanout-fanin</module>
-    <module>feature-toggle</module>
-    <module>filterer</module>
-    <module>fluent-interface</module>
-    <module>flux</module>
-    <module>flyweight</module>
-    <module>front-controller</module>
-    <module>function-composition</module>
-    <module>game-loop</module>
-    <module>gateway</module>
-    <module>guarded-suspension</module>
-    <module>half-sync-half-async</module>
-    <module>health-check</module>
-    <module>hexagonal-architecture</module>
-    <module>identity-map</module>
-    <module>immutable</module>
-    <module>intercepting-filter</module>
-    <module>interpreter</module>
-    <module>iterator</module>
-    <module>layered-architecture</module>
-    <module>lazy-loading</module>
-    <module>leader-election</module>
-    <module>leader-followers</module>
-    <module>lockable-object</module>
-    <module>map-reduce</module>
-    <module>marker-interface</module>
-    <module>master-worker</module>
-    <module>mediator</module>
-    <module>memento</module>
-    <module>metadata-mapping</module>
-    <module>microservices-aggregrator</module>
-    <module>microservices-api-gateway</module>
-    <module>microservices-client-side-ui-composition</module>
-    <module>microservices-distributed-tracing</module>
-    <module>microservices-idempotent-consumer</module>
-    <module>microservices-log-aggregation</module>
-    <module>microservices-self-registration</module>
-    <module>model-view-controller</module>
-    <module>model-view-intent</module>
-    <module>model-view-presenter</module>
-    <module>model-view-viewmodel</module>
-    <module>monad</module>
-    <module>money</module>
-    <module>monitor</module>
-    <module>monolithic-architecture</module>
-    <module>monostate</module>
-    <module>multiton</module>
-    <module>mute-idiom</module>
-    <module>notification</module>
-    <module>null-object</module>
-    <module>object-mother</module>
-    <module>object-pool</module>
-    <module>observer</module>
-    <module>optimistic-offline-lock</module>
-    <module>page-controller</module>
-    <module>page-object</module>
-    <module>parameter-object</module>
-    <module>partial-response</module>
-    <module>pipeline</module>
-    <module>poison-pill</module>
-    <module>polling-publisher</module>
-    <module>presentation-model</module>
-    <module>private-class-data</module>
-    <module>producer-consumer</module>
-    <module>promise</module>
-    <module>property</module>
-    <module>prototype</module>
-    <module>proxy</module>
-    <module>publish-subscribe</module>
-    <module>queue-based-load-leveling</module>
-    <module>reactor</module>
-    <module>registry</module>
-    <module>repository</module>
-    <module>resource-acquisition-is-initialization</module>
-    <module>retry</module>
-    <module>role-object</module>
-    <module>saga</module>
-    <module>separated-interface</module>
-    <module>serialized-entity</module>
-    <module>serialized-lob</module>
-    <module>servant</module>
-    <module>server-session</module>
-    <module>service-layer</module>
-    <module>service-locator</module>
-    <module>service-stub</module>
-    <module>service-to-worker</module>
-    <module>session-facade</module>
-    <module>sharding</module>
-    <module>single-table-inheritance</module>
-    <module>singleton</module>
-    <module>spatial-partition</module>
-    <module>special-case</module>
-    <module>specification</module>
-    <module>state</module>
-    <module>step-builder</module>
-    <module>strangler</module>
-    <module>strategy</module>
-    <module>subclass-sandbox</module>
-    <module>table-inheritance</module>
-    <module>table-module</module>
-    <module>template-method</module>
-    <module>templateview</module>
-    <module>thread-pool-executor</module>
-    <module>thread-specific-storage</module>
-    <module>throttling</module>
-    <module>tolerant-reader</module>
-    <module>trampoline</module>
-    <module>transaction-script</module>
-    <module>twin</module>
-    <module>type-object</module>
-    <module>unit-of-work</module>
-    <module>update-method</module>
-    <module>value-object</module>
-    <module>version-number</module>
-    <module>view-helper</module>
-    <module>virtual-proxy</module>
-    <module>visitor</module>
-    <module>backpressure</module>
-    <module>actor-model</module>
-    <module>rate-limiting-pattern</module>
-  </modules>
-  <repositories>
-    <repository>
-      <id>jitpack.io</id>
-      <url>https://jitpack.io</url>
-    </repository>
-  </repositories>
-  <dependencyManagement>
+        <!-- SonarCloud -->
+        <sonar-maven-plugin.version>5.1.0.4751</sonar-maven-plugin.version>
+        <sonar.host.url>https://sonarcloud.io</sonar.host.url>
+        <sonar.organization>iluwatar</sonar.organization>
+        <sonar.projectKey>iluwatar_java-design-patterns</sonar.projectKey>
+        <sonar.moduleKey>${project.artifactId}</sonar.moduleKey>
+        <sonar.projectName>Java Design Patterns</sonar.projectName>
+    </properties>
+    <modules>
+        <module>abstract-document</module>
+        <module>abstract-factory</module>
+        <module>active-object</module>
+        <module>acyclic-visitor</module>
+        <module>adapter</module>
+        <module>ambassador</module>
+        <module>anti-corruption-layer</module>
+        <module>arrange-act-assert</module>
+        <module>async-method-invocation</module>
+        <module>balking</module>
+        <module>bloc</module>
+        <module>bridge</module>
+        <module>builder</module>
+        <module>business-delegate</module>
+        <module>bytecode</module>
+        <module>caching</module>
+        <module>callback</module>
+        <module>chain-of-responsibility</module>
+        <module>circuit-breaker</module>
+        <module>clean-architecture</module>
+        <module>client-session</module>
+        <module>collecting-parameter</module>
+        <module>collection-pipeline</module>
+        <module>combinator</module>
+        <module>command</module>
+        <module>command-query-responsibility-segregation</module>
+        <module>commander</module>
+        <module>component</module>
+        <module>composite</module>
+        <module>composite-entity</module>
+        <module>composite-view</module>
+        <module>context-object</module>
+        <module>converter</module>
+        <module>curiously-recurring-template-pattern</module>
+        <module>currying</module>
+        <module>dao-factory</module>
+        <module>data-access-object</module>
+        <module>data-bus</module>
+        <module>data-locality</module>
+        <module>data-mapper</module>
+        <module>data-transfer-object</module>
+        <module>decorator</module>
+        <module>delegation</module>
+        <module>dependency-injection</module>
+        <module>dirty-flag</module>
+        <module>domain-model</module>
+        <module>double-buffer</module>
+        <module>double-checked-locking</module>
+        <module>double-dispatch</module>
+        <module>dynamic-proxy</module>
+        <module>event-aggregator</module>
+        <module>event-based-asynchronous</module>
+        <module>event-driven-architecture</module>
+        <module>event-queue</module>
+        <module>event-sourcing</module>
+        <module>execute-around</module>
+        <module>extension-objects</module>
+        <module>facade</module>
+        <module>factory</module>
+        <module>factory-kit</module>
+        <module>factory-method</module>
+        <module>fanout-fanin</module>
+        <module>feature-toggle</module>
+        <module>filterer</module>
+        <module>fluent-interface</module>
+        <module>flux</module>
+        <module>flyweight</module>
+        <module>front-controller</module>
+        <module>function-composition</module>
+        <module>game-loop</module>
+        <module>gateway</module>
+        <module>guarded-suspension</module>
+        <module>half-sync-half-async</module>
+        <module>health-check</module>
+        <module>hexagonal-architecture</module>
+        <module>identity-map</module>
+        <module>immutable</module>
+        <module>intercepting-filter</module>
+        <module>interpreter</module>
+        <module>iterator</module>
+        <module>layered-architecture</module>
+        <module>lazy-loading</module>
+        <module>leader-election</module>
+        <module>leader-followers</module>
+        <module>lockable-object</module>
+        <module>map-reduce</module>
+        <module>marker-interface</module>
+        <module>master-worker</module>
+        <module>mediator</module>
+        <module>memento</module>
+        <module>metadata-mapping</module>
+        <module>microservices-aggregrator</module>
+        <module>microservices-api-gateway</module>
+        <module>microservices-client-side-ui-composition</module>
+        <module>microservices-distributed-tracing</module>
+        <module>microservices-idempotent-consumer</module>
+        <module>microservices-log-aggregation</module>
+        <module>microservices-self-registration</module>
+        <module>model-view-controller</module>
+        <module>model-view-intent</module>
+        <module>model-view-presenter</module>
+        <module>model-view-viewmodel</module>
+        <module>monad</module>
+        <module>money</module>
+        <module>monitor</module>
+        <module>monolithic-architecture</module>
+        <module>monostate</module>
+        <module>multiton</module>
+        <module>mute-idiom</module>
+        <module>notification</module>
+        <module>null-object</module>
+        <module>object-mother</module>
+        <module>object-pool</module>
+        <module>observer</module>
+        <module>optimistic-offline-lock</module>
+        <module>page-controller</module>
+        <module>page-object</module>
+        <module>parameter-object</module>
+        <module>partial-response</module>
+        <module>pipeline</module>
+        <module>poison-pill</module>
+        <module>polling-publisher</module>
+        <module>presentation-model</module>
+        <module>private-class-data</module>
+        <module>producer-consumer</module>
+        <module>promise</module>
+        <module>property</module>
+        <module>prototype</module>
+        <module>proxy</module>
+        <module>publish-subscribe</module>
+        <module>queue-based-load-leveling</module>
+        <module>reactor</module>
+        <module>registry</module>
+        <module>remote-procedure-invocation</module>
+        <module>repository</module>
+        <module>resource-acquisition-is-initialization</module>
+        <module>retry</module>
+        <module>role-object</module>
+        <module>saga</module>
+        <module>separated-interface</module>
+        <module>serialized-entity</module>
+        <module>serialized-lob</module>
+        <module>servant</module>
+        <module>server-session</module>
+        <module>service-layer</module>
+        <module>service-locator</module>
+        <module>service-stub</module>
+        <module>service-to-worker</module>
+        <module>session-facade</module>
+        <module>sharding</module>
+        <module>single-table-inheritance</module>
+        <module>singleton</module>
+        <module>spatial-partition</module>
+        <module>special-case</module>
+        <module>specification</module>
+        <module>state</module>
+        <module>step-builder</module>
+        <module>strangler</module>
+        <module>strategy</module>
+        <module>subclass-sandbox</module>
+        <module>table-inheritance</module>
+        <module>table-module</module>
+        <module>template-method</module>
+        <module>templateview</module>
+        <module>thread-pool-executor</module>
+        <module>thread-specific-storage</module>
+        <module>throttling</module>
+        <module>tolerant-reader</module>
+        <module>trampoline</module>
+        <module>transaction-script</module>
+        <module>twin</module>
+        <module>type-object</module>
+        <module>unit-of-work</module>
+        <module>update-method</module>
+        <module>value-object</module>
+        <module>version-number</module>
+        <module>view-helper</module>
+        <module>virtual-proxy</module>
+        <module>visitor</module>
+        <module>backpressure</module>
+        <module>actor-model</module>
+        <module>rate-limiting-pattern</module>
+    </modules>
+    <repositories>
+        <repository>
+            <id>jitpack.io</id>
+            <url>https://jitpack.io</url>
+        </repository>
+    </repositories>
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-starter</artifactId>
+                <version>${spring-boot.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-starter-web</artifactId>
+                <version>${spring-boot.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-starter-actuator</artifactId>
+                <version>${spring-boot.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-starter-data-jpa</artifactId>
+                <version>${spring-boot.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-starter-test</artifactId>
+                <scope>test</scope>
+                <version>${spring-boot.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>commons-dbcp</groupId>
+                <artifactId>commons-dbcp</artifactId>
+                <version>${commons-dbcp.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.htmlunit</groupId>
+                <artifactId>htmlunit</artifactId>
+                <version>${htmlunit.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>com.google.code.gson</groupId>
+                <artifactId>gson</artifactId>
+                <version>${gson.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>com.google.inject</groupId>
+                <artifactId>guice</artifactId>
+                <version>${guice.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>com.github.stefanbirkner</groupId>
+                <artifactId>system-lambda</artifactId>
+                <version>${system-lambda.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.junit.jupiter</groupId>
+                <artifactId>junit-jupiter-engine</artifactId>
+                <version>${junit.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.junit.jupiter</groupId>
+                <artifactId>junit-jupiter-params</artifactId>
+                <version>${junit.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.junit.jupiter</groupId>
+                <artifactId>junit-jupiter-migrationsupport</artifactId>
+                <version>${junit.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.slf4j</groupId>
+                <artifactId>slf4j-api</artifactId>
+                <version>${slf4j.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>ch.qos.logback</groupId>
+                <artifactId>logback-classic</artifactId>
+                <version>${logback.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.mockito</groupId>
+                <artifactId>mockito-core</artifactId>
+                <version>${mockito.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.mongodb</groupId>
+                <artifactId>bson</artifactId>
+                <version>${bson.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.mongodb</groupId>
+                <artifactId>mongodb-driver-legacy</artifactId>
+                <version>${mongo.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>com.h2database</groupId>
+                <artifactId>h2</artifactId>
+                <version>${h2.version}</version>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
     <dependencies>
-      <dependency>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter</artifactId>
-        <version>${spring-boot.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-web</artifactId>
-        <version>${spring-boot.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-actuator</artifactId>
-        <version>${spring-boot.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-data-jpa</artifactId>
-        <version>${spring-boot.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-test</artifactId>
-        <scope>test</scope>
-        <version>${spring-boot.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>commons-dbcp</groupId>
-        <artifactId>commons-dbcp</artifactId>
-        <version>${commons-dbcp.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.htmlunit</groupId>
-        <artifactId>htmlunit</artifactId>
-        <version>${htmlunit.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>com.google.code.gson</groupId>
-        <artifactId>gson</artifactId>
-        <version>${gson.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>com.google.inject</groupId>
-        <artifactId>guice</artifactId>
-        <version>${guice.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>com.github.stefanbirkner</groupId>
-        <artifactId>system-lambda</artifactId>
-        <version>${system-lambda.version}</version>
-        <scope>test</scope>
-      </dependency>
-      <dependency>
-        <groupId>org.junit.jupiter</groupId>
-        <artifactId>junit-jupiter-engine</artifactId>
-        <version>${junit.version}</version>
-        <scope>test</scope>
-      </dependency>
-      <dependency>
-        <groupId>org.junit.jupiter</groupId>
-        <artifactId>junit-jupiter-params</artifactId>
-        <version>${junit.version}</version>
-        <scope>test</scope>
-      </dependency>
-      <dependency>
-        <groupId>org.junit.jupiter</groupId>
-        <artifactId>junit-jupiter-migrationsupport</artifactId>
-        <version>${junit.version}</version>
-        <scope>test</scope>
-      </dependency>
-      <dependency>
-        <groupId>org.slf4j</groupId>
-        <artifactId>slf4j-api</artifactId>
-        <version>${slf4j.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>ch.qos.logback</groupId>
-        <artifactId>logback-classic</artifactId>
-        <version>${logback.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.mockito</groupId>
-        <artifactId>mockito-core</artifactId>
-        <version>${mockito.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.mongodb</groupId>
-        <artifactId>bson</artifactId>
-        <version>${bson.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>org.mongodb</groupId>
-        <artifactId>mongodb-driver-legacy</artifactId>
-        <version>${mongo.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>com.h2database</groupId>
-        <artifactId>h2</artifactId>
-        <version>${h2.version}</version>
-      </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
     </dependencies>
-  </dependencyManagement>
-  <dependencies>
-    <dependency>
-      <groupId>org.projectlombok</groupId>
-      <artifactId>lombok</artifactId>
-      <version>${lombok.version}</version>
-      <scope>provided</scope>
-    </dependency>
-  </dependencies>
-  <build>
-    <pluginManagement>
-      <plugins>
-        <plugin>
-          <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-compiler-plugin</artifactId>
-          <version>${maven-compiler-plugin.version}</version>
-          <configuration>
-            <source>21</source>
-            <target>21</target>
-            <annotationProcessorPaths>
-              <path>
-                <groupId>org.projectlombok</groupId>
-                <artifactId>lombok</artifactId>
-                <version>${lombok.version}</version>
-              </path>
-            </annotationProcessorPaths>
-          </configuration>
-        </plugin>
-        <plugin>
-          <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-surefire-plugin</artifactId>
-          <version>${maven-surefire-plugin.version}</version>
-        </plugin>
-        <plugin>
-          <groupId>org.springframework.boot</groupId>
-          <artifactId>spring-boot-maven-plugin</artifactId>
-        </plugin>
-        <!-- Maven assembly plugin template for all child project to follow -->
-        <plugin>
-          <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-assembly-plugin</artifactId>
-          <executions>
-            <execution>
-              <phase>package</phase>
-              <goals>
-                <goal>single</goal>
-              </goals>
-              <configuration>
-                <descriptorRefs>
-                  <descriptorRef>jar-with-dependencies</descriptorRef>
-                </descriptorRefs>
-                <!-- below two line make sure the fat jar is sharing the same name as of project name -->
-                <finalName>${project.artifactId}-${project.version}</finalName>
-                <appendAssemblyId>false</appendAssemblyId>
-              </configuration>
-            </execution>
-          </executions>
-        </plugin>
-        <plugin>
-          <groupId>org.sonarsource.scanner.maven</groupId>
-          <artifactId>sonar-maven-plugin</artifactId>
-          <version>${sonar-maven-plugin.version}</version>
-        </plugin>
-      </plugins>
-    </pluginManagement>
-    <plugins>
-      <plugin>
-        <groupId>com.mycila</groupId>
-        <artifactId>license-maven-plugin</artifactId>
-        <version>${license-maven-plugin.version}</version>
-        <configuration>
-          <licenseSets>
-            <licenseSet>
-              <multi>
-                <preamble><![CDATA[This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).]]></preamble>
-                <header>com/mycila/maven/plugin/license/templates/MIT.txt</header>
-              </multi>
-              <excludes>
-                <exclude>**/README</exclude>
-                <exclude>src/test/resources/**</exclude>
-                <exclude>src/main/resources/**</exclude>
-                <exclude>checkstyle-suppressions.xml</exclude>
-              </excludes>
-            </licenseSet>
-          </licenseSets>
-          <properties>
-            <owner>Ilkka Seppälä</owner>
-            <email>iluwatar@gmail.com</email>
-          </properties>
-        </configuration>
-        <executions>
-          <execution>
-            <id>install-format</id>
-            <phase>install</phase>
-            <goals>
-              <goal>format</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
-      <plugin>
-        <groupId>org.jacoco</groupId>
-        <artifactId>jacoco-maven-plugin</artifactId>
-        <version>${jacoco.version}</version>
-        <executions>
-          <execution>
-            <id>prepare-agent</id>
-            <goals>
-              <goal>prepare-agent</goal>
-            </goals>
-          </execution>
-          <execution>
-            <id>report</id>
-            <goals>
-              <goal>report</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
-      <plugin>
-        <groupId>com.diffplug.spotless</groupId>
-        <artifactId>spotless-maven-plugin</artifactId>
-        <version>2.44.4</version> <!-- Use latest version -->
-        <executions>
-          <execution>
-            <goals>
-              <goal>check</goal>     <!-- Run to check formatting -->
-              <goal>apply</goal>     <!-- Run to format automatically -->
-            </goals>
-          </execution>
-        </executions>
-        <configuration>
-          <java>
-            <googleJavaFormat>
-              <version>1.17.0</version> <!-- Optional: choose the GJF version -->
-            </googleJavaFormat>
-          </java>
-        </configuration>
-      </plugin>
-    </plugins>
-  </build>
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>${maven-compiler-plugin.version}</version>
+                    <configuration>
+                        <source>21</source>
+                        <target>21</target>
+                        <annotationProcessorPaths>
+                            <path>
+                                <groupId>org.projectlombok</groupId>
+                                <artifactId>lombok</artifactId>
+                                <version>${lombok.version}</version>
+                            </path>
+                        </annotationProcessorPaths>
+                    </configuration>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>${maven-surefire-plugin.version}</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.springframework.boot</groupId>
+                    <artifactId>spring-boot-maven-plugin</artifactId>
+                </plugin>
+                <!-- Maven assembly plugin template for all child project to follow -->
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-assembly-plugin</artifactId>
+                    <executions>
+                        <execution>
+                            <phase>package</phase>
+                            <goals>
+                                <goal>single</goal>
+                            </goals>
+                            <configuration>
+                                <descriptorRefs>
+                                    <descriptorRef>jar-with-dependencies</descriptorRef>
+                                </descriptorRefs>
+                                <!-- below two line make sure the fat jar is sharing the same name as of project name -->
+                                <finalName>${project.artifactId}-${project.version}</finalName>
+                                <appendAssemblyId>false</appendAssemblyId>
+                            </configuration>
+                        </execution>
+                    </executions>
+                </plugin>
+                <plugin>
+                    <groupId>org.sonarsource.scanner.maven</groupId>
+                    <artifactId>sonar-maven-plugin</artifactId>
+                    <version>${sonar-maven-plugin.version}</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+        <plugins>
+            <plugin>
+                <groupId>com.mycila</groupId>
+                <artifactId>license-maven-plugin</artifactId>
+                <version>${license-maven-plugin.version}</version>
+                <configuration>
+                    <licenseSets>
+                        <licenseSet>
+                            <multi>
+                                <preamble><![CDATA[This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).]]></preamble>
+                                <header>com/mycila/maven/plugin/license/templates/MIT.txt</header>
+                            </multi>
+                            <excludes>
+                                <exclude>**/README</exclude>
+                                <exclude>src/test/resources/**</exclude>
+                                <exclude>src/main/resources/**</exclude>
+                                <exclude>checkstyle-suppressions.xml</exclude>
+                            </excludes>
+                        </licenseSet>
+                    </licenseSets>
+                    <properties>
+                        <owner>Ilkka Seppälä</owner>
+                        <email>iluwatar@gmail.com</email>
+                    </properties>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>install-format</id>
+                        <phase>install</phase>
+                        <goals>
+                            <goal>format</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.jacoco</groupId>
+                <artifactId>jacoco-maven-plugin</artifactId>
+                <version>${jacoco.version}</version>
+                <executions>
+                    <execution>
+                        <id>prepare-agent</id>
+                        <goals>
+                            <goal>prepare-agent</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>report</id>
+                        <goals>
+                            <goal>report</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <version>2.44.4</version> <!-- Use latest version -->
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>check</goal>     <!-- Run to check formatting -->
+                            <goal>apply</goal>     <!-- Run to format automatically -->
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <java>
+                        <googleJavaFormat>
+                            <version>1.17.0</version> <!-- Optional: choose the GJF version -->
+                        </googleJavaFormat>
+                    </java>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 </project>
diff --git a/remote-procedure-invocation/README.md b/remote-procedure-invocation/README.md
new file mode 100644
index 000000000000..810c8a1e4d26
--- /dev/null
+++ b/remote-procedure-invocation/README.md
@@ -0,0 +1,126 @@
+---
+title: "Remote Procedure Invocation (RPI) Pattern in Java: Synchronous Communication Between Microservices"
+shortTitle: Remote Procedure Invocation
+description: "Learn the Remote Procedure Invocation (RPI) pattern in Java for enabling synchronous request/reply communication between microservices using REST and Spring Boot."
+category: Integration
+language: en
+tag:
+  - Client-server
+  - Decoupling
+  - Integration
+  - Microservices
+  - Synchronous
+---
+## Also Known As
+
+* Remote Procedure Call (RPC)
+
+## Intent of Remote Procedure Invocation Pattern
+
+Enable synchronous communication between microservices using a request/reply protocol such as REST, where a client makes a direct call to a remote service and blocks until the response is received.
+
+## Detailed Explanation of Remote Procedure Invocation Pattern with Real-World Examples
+
+Real-world example
+
+> Consider an e-commerce application where the checkout service needs to verify a customer's shipping address by calling the address-validation service. The checkout service sends an HTTP request with the address details and waits for the validation result before proceeding. This synchronous request/reply interaction is the essence of RPI — direct, blocking communication between two services without an intermediate message broker.
+
+In plain words
+
+> Remote Procedure Invocation lets one microservice call another over the network using a request/reply protocol (typically HTTP/REST) as if calling a local method, while both must be available at the time of the call.
+
+## Programmatic Example of Remote Procedure Invocation Pattern in Java
+
+This example demonstrates a simple RPI setup using Spring Boot. The `RpiService` exposes a REST endpoint, and the `RpiClient` uses `RestTemplate` to call it synchronously.
+
+**The Service (Server Side)**
+
+The `RpiService` is a Spring `@RestController` that exposes a `/greet` endpoint:
+
+```java
+@RestController
+public class RpiService {
+
+  @GetMapping("/greet")
+  public String greet(@RequestParam(defaultValue = "World") String name) {
+    return "Hello, " + name + "!";
+  }
+}
+```
+**The Client**
+
+The `RpiClient` uses `RestTemplate` to make a synchronous HTTP GET request to the service:
+```java
+@Slf4j
+public class RpiClient {
+
+  private final RestTemplate restTemplate;
+  private final String baseUrl;
+
+  public RpiClient(RestTemplate restTemplate, String baseUrl) {
+    this.restTemplate = restTemplate;
+    this.baseUrl = baseUrl;
+  }
+
+  public String greet(String name) {
+    var url = baseUrl + "/greet?name=" + name;
+    LOGGER.info("Calling remote service: {}", url);
+    var response = restTemplate.getForObject(url, String.class);
+    LOGGER.info("Received response: {}", response);
+    return response;
+  }
+}
+```
+**Running the example**
+
+Start the application and then make a call:
+
+```bash
+curl http://localhost:8080/greet?name=Java
+```
+**Console Output**
+```bash
+Hello, Java!
+```
+## When to Use the Remote Procedure Invocation Pattern in Java
+
+* When services need synchronous request/reply communication.
+* When simplicity is preferred over asynchronous messaging infrastructure.
+* When the client needs an immediate response from the service before proceeding.
+
+## Remote Procedure Invocation Pattern Class Diagram
+
+![Remote Procedure Invocation](./etc/rpi.urm.png)
+
+## Real-World Applications of Remote Procedure Invocation Pattern in Java
+
+* RESTful API calls between microservices using `RestTemplate` or `WebClient`.
+* gRPC-based service-to-service communication.
+* Any HTTP-based synchronous inter-service call in a microservice architecture.
+
+## Benefits and Trade-offs of Remote Procedure Invocation Pattern
+
+Benefits:
+
+* Simple and familiar programming model — similar to calling a local method.
+* No need for intermediate message broker infrastructure.
+* Easy to understand, debug, and trace.
+
+Trade-offs:
+
+* Tight runtime coupling — both client and service must be available simultaneously.
+* Reduced availability — if the service is down, the client call fails.
+* Potential for cascading failures without resilience patterns like Circuit Breaker.
+* Synchronous blocking can limit throughput under high load.
+
+## Related Java Design Patterns
+
+* [Circuit Breaker](https://java-design-patterns.com/patterns/circuit-breaker/): Protects clients from cascading failures when a remote service is unavailable.
+* [Ambassador](https://java-design-patterns.com/patterns/ambassador/): Can act as a proxy for remote service calls, adding retry, logging, or monitoring.
+* [Gateway](https://java-design-patterns.com/patterns/gateway/): Provides a single entry point that routes RPI calls to the appropriate backend service.
+
+## References and Credits
+
+* [Microservices Patterns: With examples in Java](https://amzn.to/3UyWD5O)
+* [Pattern: Remote Procedure Invocation (microservices.io)](https://microservices.io/patterns/communication-style/rpi.html)
+* [Spring Boot Documentation](https://spring.io/projects/spring-boot)
\ No newline at end of file
diff --git a/remote-procedure-invocation/etc/rpi.urm.png b/remote-procedure-invocation/etc/rpi.urm.png
new file mode 100644
index 000000000000..c11ca6f2212a
Binary files /dev/null and b/remote-procedure-invocation/etc/rpi.urm.png differ
diff --git a/remote-procedure-invocation/etc/rpi.urm.puml b/remote-procedure-invocation/etc/rpi.urm.puml
new file mode 100644
index 000000000000..fa32df54bb6c
--- /dev/null
+++ b/remote-procedure-invocation/etc/rpi.urm.puml
@@ -0,0 +1,18 @@
+@startuml
+package com.iluwatar.rpi {
+  class App {
+    + main(args : String[]) {static}
+  }
+  class RpiService {
+    + greet(name : String) : String
+  }
+  class RpiClient {
+    - restTemplate : RestTemplate
+    - baseUrl : String
+    + RpiClient(restTemplate : RestTemplate, baseUrl : String)
+    + greet(name : String) : String
+  }
+}
+
+RpiClient ..> RpiService : <<HTTP GET /greet>>
+@enduml
\ No newline at end of file
diff --git a/remote-procedure-invocation/pom.xml b/remote-procedure-invocation/pom.xml
new file mode 100644
index 000000000000..22191d197815
--- /dev/null
+++ b/remote-procedure-invocation/pom.xml
@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+
+    The MIT License
+    Copyright © 2014-2022 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.iluwatar</groupId>
+        <artifactId>java-design-patterns</artifactId>
+        <version>1.26.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>remote-procedure-invocation</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <configuration>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.iluwatar.rpi.App</mainClass>
+                                </manifest>
+                            </archive>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>
\ No newline at end of file
diff --git a/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/App.java b/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/App.java
new file mode 100644
index 000000000000..2026ca4808f4
--- /dev/null
+++ b/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/App.java
@@ -0,0 +1,60 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.rpi;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Remote Procedure Invocation (RPI) is a communication pattern used in microservices architectures
+ * where a client sends a synchronous request to a service and waits for a response. Unlike
+ * message-based communication, RPI uses a direct request/reply protocol — typically REST over HTTP.
+ *
+ * <p>In this example, the {@link RpiService} exposes a REST endpoint that returns a greeting
+ * message. The {@link RpiClient} uses Spring's {@link org.springframework.web.client.RestTemplate}
+ * to make a synchronous HTTP GET call to the service and retrieve the response.
+ *
+ * <p>Key characteristics of RPI:
+ *
+ * <ul>
+ *   <li>Synchronous communication — the client blocks until the response arrives.
+ *   <li>Simple and familiar — leverages standard HTTP/REST protocols.
+ *   <li>No intermediate broker — direct client-to-service communication.
+ *   <li>Both client and service must be available at the time of the call (tight runtime coupling).
+ * </ul>
+ *
+ * @see <a href="https://microservices.io/patterns/communication-style/rpi.html">RPI Pattern</a>
+ */
+@SpringBootApplication
+public class App {
+
+  /** Program entry point. */
+  public static void main(String[] args) {
+    var context = SpringApplication.run(App.class, args);
+    if (args.length > 0 && "test".equals(args[0])) {
+      context.close();
+    }
+  }
+}
\ No newline at end of file
diff --git a/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/RpiClient.java b/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/RpiClient.java
new file mode 100644
index 000000000000..390c98fcddd9
--- /dev/null
+++ b/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/RpiClient.java
@@ -0,0 +1,65 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.rpi;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.web.client.RestTemplate;
+
+/**
+ * The client-side component of the RPI pattern. Uses {@link RestTemplate} to make a synchronous
+ * HTTP GET request to the remote {@link RpiService} and returns the response. This demonstrates the
+ * core of RPI — a client blocking on a remote call and waiting for the result.
+ */
+@Slf4j
+public class RpiClient {
+
+  private final RestTemplate restTemplate;
+  private final String baseUrl;
+
+  /**
+   * Creates a new RpiClient.
+   *
+   * @param restTemplate the RestTemplate used to perform HTTP calls
+   * @param baseUrl the base URL of the remote service (e.g. "http://localhost:8080")
+   */
+  public RpiClient(RestTemplate restTemplate, String baseUrl) {
+    this.restTemplate = restTemplate;
+    this.baseUrl = baseUrl;
+  }
+
+  /**
+   * Invokes the remote greeting service with the given name.
+   *
+   * @param name the name to send to the remote service
+   * @return the greeting response from the service
+   */
+  public String greet(String name) {
+    var url = baseUrl + "/greet?name=" + name;
+    LOGGER.info("Calling remote service: {}", url);
+    var response = restTemplate.getForObject(url, String.class);
+    LOGGER.info("Received response: {}", response);
+    return response;
+  }
+}
\ No newline at end of file
diff --git a/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/RpiService.java b/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/RpiService.java
new file mode 100644
index 000000000000..b7116dce365c
--- /dev/null
+++ b/remote-procedure-invocation/src/main/java/com/iluwatar/rpi/RpiService.java
@@ -0,0 +1,49 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.rpi;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * The server-side component of the RPI pattern. This REST controller exposes an endpoint that
+ * accepts a name parameter and returns a greeting string. It represents the service that clients
+ * invoke remotely using a request/reply protocol.
+ */
+@RestController
+public class RpiService {
+
+  /**
+   * Returns a greeting message for the given name.
+   *
+   * @param name the name to greet
+   * @return a greeting string
+   */
+  @GetMapping("/greet")
+  public String greet(@RequestParam(defaultValue = "World") String name) {
+    return "Hello, " + name + "!";
+  }
+}
\ No newline at end of file
diff --git a/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/AppTest.java b/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/AppTest.java
new file mode 100644
index 000000000000..240992c1d85c
--- /dev/null
+++ b/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/AppTest.java
@@ -0,0 +1,89 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.rpi;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.test.web.server.LocalServerPort;
+
+/**
+ * Tests for the Remote Procedure Invocation pattern.
+ */
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class AppTest {
+
+  @LocalServerPort
+  private int port;
+
+  @Autowired
+  private TestRestTemplate testRestTemplate;
+
+  /**
+   * Verify that the application starts without exception.
+   */
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[] {"test"}));
+  }
+
+  /**
+   * Verify that the /greet endpoint returns a greeting with default name.
+   */
+  @Test
+  void shouldReturnDefaultGreeting() {
+    var response =
+        testRestTemplate.getForObject("http://localhost:" + port + "/greet", String.class);
+    assertEquals("Hello, World!", response);
+  }
+
+  /**
+   * Verify that the /greet endpoint returns a greeting with a custom name.
+   */
+  @Test
+  void shouldReturnCustomGreeting() {
+    var response =
+        testRestTemplate.getForObject(
+            "http://localhost:" + port + "/greet?name=Java", String.class);
+    assertEquals("Hello, Java!", response);
+  }
+
+  /**
+   * Verify that the RpiClient correctly calls the service and receives a response.
+   */
+  @Test
+  void shouldClientReceiveGreetingFromService() {
+    var client =
+        new RpiClient(
+            testRestTemplate.getRestTemplate(), "http://localhost:" + port);
+    var result = client.greet("RPI");
+    assertEquals("Hello, RPI!", result);
+  }
+}
\ No newline at end of file
diff --git a/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/RpiClientTest.java b/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/RpiClientTest.java
new file mode 100644
index 000000000000..cd4efad857c2
--- /dev/null
+++ b/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/RpiClientTest.java
@@ -0,0 +1,53 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.rpi;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.web.client.RestTemplate;
+
+/** Unit tests for {@link RpiClient} using a mocked {@link RestTemplate}. */
+@ExtendWith(MockitoExtension.class)
+class RpiClientTest {
+
+  @Mock private RestTemplate restTemplate;
+
+  @Test
+  void shouldReturnGreetingFromRemoteService() {
+    var baseUrl = "http://localhost:8080";
+    var client = new RpiClient(restTemplate, baseUrl);
+
+    when(restTemplate.getForObject(baseUrl + "/greet?name=Alice", String.class))
+        .thenReturn("Hello, Alice!");
+
+    var result = client.greet("Alice");
+    assertEquals("Hello, Alice!", result);
+  }
+}
\ No newline at end of file
diff --git a/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/RpiServiceTest.java b/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/RpiServiceTest.java
new file mode 100644
index 000000000000..4f4e42072640
--- /dev/null
+++ b/remote-procedure-invocation/src/test/java/com/iluwatar/rpi/RpiServiceTest.java
@@ -0,0 +1,45 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.rpi;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/** Unit tests for {@link RpiService}. */
+class RpiServiceTest {
+
+  private final RpiService service = new RpiService();
+
+  @Test
+  void shouldGreetWithGivenName() {
+    assertEquals("Hello, Alice!", service.greet("Alice"));
+  }
+
+  @Test
+  void shouldGreetWithDefaultName() {
+    assertEquals("Hello, World!", service.greet("World"));
+  }
+}
\ No newline at end of file