Usually to sync a table with in the network I can write a simple sql query and run it to sync the tables, but what if the source database is different(could be db2, mssql, mysql, oracle - from where I can get the data in to destination table).

How should I go about writing the code in java to achieve this?. I know I can create dblinks in java to fetch data from external network database but dblinks works only with database of same type. I am not able to figure out the implementation in my head. Please point me in the right direction so I can take baby steps and learn the same as I am new to java