ChainBuilder ESB is Java Business Integration (JBI) compliant open source solution for use in Service Oriented Architecture (SOA) environments. ChainBuilder ESB's graphical integration enables new and older applications to easily enter into SOA.
Apache Camel is a powerful rule based routing and mediation engine which provides a POJO based implementation of the Enterprise Integration Patterns using an extremely powerful fluent API (or declarative Java Domain Specific Language) to configure routing and mediation rules. The Domain Specific Language means that Apache Camel can support type-safe smart completion of routing rules in your IDE using regular Java code without huge amounts of XML configuration files; though Xml Configuration inside Spring is also supported.
One of the biggest promises of Business Process Management was that the business people can model and execute their business processes without involvement from IT folks. This promise was kept in a simple workflow sceanarios by utilizing limited number of 'built-in' activity types of BPMS packages but once you face little more complex business process sceanarios providing transactional integration with existing software and complex interactions with human beings, this limited expression power make it hard to drag and drop process modeling, and finally it brings a huge help from software vendors or system integrators and write a lot of code that is making processes utterly inflexible downstream. That means, concurrent BPMS is extremely lack in something like 'Technical Abstraction' and 'Expression Extensibility'.