> I am very new to java and I am working on a web app where I can show
> only 20 regs per page, sort of VB app with Next-Prev-First-Last
> buttons.
>
> It this possible with Firebird and Java?

Java has very little to do with it, it is a feature of Firebird:

SELECT FIRST m SKIP n <list of columns> FROM <table> WHERE <condition>

m - number of records to fetch
n - number of records to skip before returning the first result

Note, you should add ORDER BY clause to guarantee that your rows are
always returned in the correct order.

Roman