Hi Rajesh,
There is a brief and nice documentation on JBPM5 which tells how to create process definition(BPMN) file and start that process with some input as HashMap.Java class which is used to start process is "SampleProcessTest.java"
Infact if you can download the source code from - https://hudson.jboss.org/hudson/job/jBPM5/lastSuccessfulBuild/artifact/target/
Build the code and run sample gwt-console application,that is also web app.
In this gwt-console application,they have two war files one for UI war(jbpm-gwt-console.war) and one for server war(jbpm-gwt-console-server.war).
These two war files can be downloaded from above link which has zip file called "jbpm-5.0-SNAPSHOT-gwt-console.zip".
So follow the documentation on JBPM5 and download their sample web app which makes restful web service call to server code and returns the data
to the UI which is build using GWT.
Link for documentation - http://hudson.jboss.org/hudson/job/jBPM5-release/lastSuccessfulBuild/artifact/target/jbpm-5.0.0-docs-build/jbpm-docs/html/index.html
Thanks,
Anand Prakash