Presently i am at tasknode1 in my sequence and i want to know what is the next node/next actor(task) to the present tasknode(i.e. tasknode1). Is there a way to find out this?
No, that's not possible as task assignments are only resolved when the task is reached at runtime. You could inspect the TaskDefinition attached to the UserTaskBehavior, this contains all information that is used during runtime assignment. Note that this will probably mean a lot of casting around, as this is definitely not the main API usage.