Oracle has its own built-in function to handle this situation: it's called Streams. Find out more. There is also Replication, but that uses materialized views rather than tables in the target database. Find out more.
Do not look at third party products or attempt to handroll your own implementation until you have considered the functionality you already have. Oracle licenses are expensive: be sure to get your money's worth.
Setting up data integration between databases is a complex subject, and not one which I would choose to hand to a beginner. However, you will find it easier to get yourself started if you use Oracle's standard functionality. The same applies to asking for help, here or in other forums.
The three key issues you have to decide on are:
synchronicity Do you want the Target DB to be completely up-to-date with the Source database? Or is it sufficient to apply updates asynchronously, perhaps even in batches? At the extreme case, synchronous updates result in distributed transactions, where two-phase commit means changes to data in Source DB must also be applied to Target DB as part of the same transaction.
structural changes It's easy enough to propagate DML changes from one schema to another, but what about DDL - new columns, new tables, etc.
directionality Will all the changes always go from Source DB to Target DB? Are there any prospects of data changes be propagated in the other direction? In a related question, can the data in Target DB be changed independently of changes in the Source DB? Or is the Target DB read only?
EDIT
The deprecated IMP/EXP utilities and the more modern DataPump functionality are intended for one-off operations. That is, importing structure and data into an empty schema, or importing data into empty objects. They are not suitable for use in a rolling synchronization operation, one where we have to be apply incremental changes. The appropriate tools for that task are the ones I have already listed: Streams or Replication.
EDIT 2
"Can you please give an example for
the same. I would be very thanful to
you."
Examples of both Replication and Streams? That would take a chunk of time, and to be quite frank I doubt you can afford my hourly rate. What I can do is point you to some handy resources on Das Interwebs. Martin Zahn has written a Replication Survival Guide which is pretty good. Tim Hall has an introduction to Streams on his Oracle-Base site; that's for 9i but it remains a decent primer. Neither of these is a substitute for the documentation, but they will help you get a handle on the different technologies.
You describe yourself as "new and very naive to Oracle DB". So you must understand that this is no trivial task. Unfortunately you can't just cut'n'paste some example code and expect it to work. You have a great deal of planning, designing and configuration ahead of you. Start by answering the questions I listed above. You need to know exactly where you are trying to reach before you make any decisions on how to get there.