user defined java class passing all the variables

Hi,
How do I pass all the variables with scope as "root" be made available to the transformation /job
executed using user defined java class?
We can do setVariable() to get for each variable. But do we have an approach/method by which by default all the variables will be passed
to the transformation or job executed by the java class?
it seems that variables set in previous steps of the same job run is not available to the transformation executed by the java class.
Regards,
Pramod.