Thanks for your reply. I had already tried in the same way. But that is not working.
For an example in the attached screen shot I am having my process and my jar file. In my process I want to create an object from the jar file but that is giving error like
Error importing : 'com.sample.dto.WFStep'
I was trying to create WFStep in my script task and I am invoking the process from my Java Code.