JDBC (executing transactions coding style)

I want to execute multiple SQL commands (also insert,updates and selects
) in a transaction block.

Is the following coding style correct ?

Statement st;
ResultSet rs;

try {
st.executeUpdate("BEGIN");
st.executeUpdate("INSERT INTO ...");
st.executeUpdate("DELETE FROM ...");
rs = st.executeQuery("SELECT FROM ...");
if (rs != null) {
while ( rs.next() ) {
// do different things
}
}
rs.close();
st.executeUpdate("UPDATE ...");
st.executeUpdate("COMMIT TRANSACTION");
} catch (SQLException sqle) {
sqle.printStackTrace();
// ABORT TRANSACTION NEEDED ?
}

What I want to know : is there necessary to do a st.executeUpdate("ABORT
TRANSACTION") in the catch instruction block ?
I recall that someone says that an error inside a transaction block
automatically aborts the transaction.
Is it true ? It works here ?

For other databases it might be necessary to do that.
Then, the st.executeUpdate("ABORT"); must be included also in another
try..catch block, true ?

Thanks a lot,
--
Constantin Teodorescu
FLEX Consulting Braila, ROMANIA