jdbc: oracle database change notification & duplicate events

Question

I need some Listener for any change(update, insert, delete) of Oracle database table.

Problem: I get many detection by single update on my table.

I think its

Answer 1

Problem was I registered to database many times. The solution was check registered user for change events before register.

I checked that with this query:

select TABLE_NAME 
from USER_CHANGE_NOTIFICATION_REGS