Both the Extended Operator and Service Callout samples contain Java projects that show how you can create the sample extension JAR yourself, and a Corticon Rules project that demonstrates those extensions.
There are two sets of extension samples:
Extended Operator Sample Projects - The Extended Operators sample contains the source code for several extended operators and a rule project that uses them. The rule project uses extended operators for determining the future value or an investment, if a collection contains duplicate strings, and if a given date is a leap year.
Service Callout Sample Projects - The Service Callout sample contains the source code for several service callouts and a rule project that uses them. The rule project uses service callouts to retrieve and update patient medical data in a pseudo external service. Accessing web services or other external datasources is a common use case for service callouts.
Extended Operator Sample Projects - The Extended Operators sample contains the source code for several extended operators and a rule project that uses them. The rule project uses extended operators for determining the future value or an investment, if a collection contains duplicate strings, and if a given date is a leap year.