Celtix was a Java Enterprise Service Bus (ESB) runtime and set of APIs to make it easy to add transports, message formats, and security features. The goal was to simplify the construction, integration and flexible reuse of technical and business components using a standards-based, service-oriented architecture.
The Celtix code base was merged with Codehaus XFire to form the Apache CXF project.
References
Celtix Wikipedia(Text) CC BY-SA