feat: Add Fork/Join design pattern (#3227) (#3550)

* Add fork-join pattern implementation

* Add input validation for start > end in SumTask

Signed-off-by: SandhyaDevadiga <sandhyadevadiga8197@gmail.com>

* Add fork-join module to parent pom.xml

* Add missing assertThrows import in SumTaskTest

* Format fork-join code with Spotless

* Add AppTest to satisfy coverage requirements

Signed-off-by: SandhyaDevadiga <sandhyadevadiga8197@gmail.com>

---------

Signed-off-by: SandhyaDevadiga <sandhyadevadiga8197@gmail.com>

fork-join/pom.xml

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    This project is licensed under the terms of the MIT license, see LICENSE.md in the root
+    of this project's GitHub repository for the full license text.
+
+    Copyright © 2014-2024 Ilkka Seppälä
+
+-->
+<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>fork-join</artifactId>
+
+  <dependencies>
+    <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.forkjoin.App</mainClass>
+                </manifest>
+              </archive>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>