Bulk insert in Java using prepared statements batch update

I am trying to fill a resultSet in Java with about 50,000 rows of 10 columns and then inserting them into another table using the batchExecute method of PreparedStatement.

To make the process faster I did some research and found that while reading data into resultSet the fetchSize plays an important role.

Having a very low fetchSize can result into too many trips to the server and a very high fetchSize can block the network resources, so I experimented a little bit and set up an optimum size that suits my infrastructure.

I am reading this resultSet and creating insert statements to insert into another table of a different database.

Something like this (just a sample, not real code):

for (i=0 ; i<=50000 ; i++) {
    statement.setString(1, "a@a.com");
    statement.setLong(2, 1);
    statement.addBatch();
}
statement.executeBatch();

• Will the executeBatch method try to send all the data at once ?
• Is there a way to define the batch size?
• Is there any better way to speed up the process of bulk insertion?

While updating in bulk (50,000 rows 10 cols), is it better to use a updatable ResultSet or PreparedStaement with batch execution?