This article needs attention from an expert on the subject. The specific problem is: Workday's developers help needed.(April 2021)
XpressO (XO) is Workday's internal programming language created for development of their business applications and it abstracts application developers from having to worry about the underlying platform, allowing them to focus on building applications of varying complexities with configurable security and access layers. These developers expose their data models and functionality through web services and REST APIs so customers can integrate with and/or extend the Workday applications.
XpressO in Workday architecture
At the heart of the architecture are the Object Management Services (OMS), a cluster of services that act as an in-memory database and host the business logic for all Workday applications. The OMS cluster is implemented in Java and runs as a servlet within Apache Tomcat. The OMS also provides the runtime for XpressO — Workday’s application programming language in which most of our business logic is implemented.
XpressO in Metadata-Driven Development