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>

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

pom.xml

@@ -139,6 +139,7 @@
     <module>fluent-interface</module>
     <module>flux</module>
     <module>flyweight</module>
+    <module>fork-join</module>
     <module>front-controller</module>
     <module>function-composition</module>
     <module>game-loop</module>