Calling user defined java classes in business rule.

Hello,

I have create jar file and loaded in mid server to create payload and pass it to ECC Queue. I was wondering if i can instantiate the class that I have written in a Business rule.

So, for example java class name with package is com.mypackage.HelloWorld()

in business rule can I do this
var val = new Packages.com.mypackage.HelloWorld();

Thanks
Vicky