JBPM6服务任务执行java代码。

I am new in JBPM6. My scenario is like this that i want to execute some java code using JBPM service task.From documentation i am not able to understand how to use domain specific process and Work Item Handler in this type of code. If someone have sample example of it please share.That will be very much helpful.I am new in JBPM6. My scenario is like this tha