Orchestra is a Web Service Orchestration Suite based on the OASIS standard BPEL (Business Process Execution Language).

NovaBPM is reference open source BPM platform embedding Bonita XPDL Workflow and Orchestra BPEL projects

JBoss jBPM is a flexible, extensible BPM management system. Business processes, expressed in a simple and powerfull language and packaged in process archives, serve as input for the JBoss jBPM runtime server. JBoss jBPM bridges the gap between managers and developers by giving them a common language : the JBoss jBPM Process definition language (jPdl). This gives software project managers much more control on their software development efforts. After loading the process archive, users or systems perform single steps of the process.

ActiveBPEL is a BPM open Source software, implementating in JAVA a BPEL engine. It reads BPEL process definitions (and other inputs such as WSDL files) and creates representations of BPEL processes. When an incoming message triggers a start activity, the engine creates a new process instance and starts it running. The engine takes care of persistence, queues, alarms, and many other execution details.

The ActiveBPEL engine runs in any standard servlet container such as Tomcat.