what is difference between JBPM and BPEL(and ESB)? Would you please explain them?
RGDS
I am not much familiar with JBPM. But it seems to be a Business work flow which can work with java services or basically java based process. Not only with web services.
BPEL is a standard to write work follows with web services. Always BPEL language used to integrate the web services and define processes based on that. Here is an sample I have written for that[1].
ESB is primarily used for mediation and transform messages. When you integrate different types of systems, the message flow between them may vary. So people can use ESB as a mediator. And also some ESBs provides service integration as well. WSO2 ESB[2] is such an ESB you can use.
[1] http://wso2.org/library/articles/2011/05/integrate-business-rules-bpel