Avoiding skipping a row By next() Method of ResultSet

Question

This is a simple code print some rows from a Database. but When I execute this nothing is print on screen. I figured that the problem is rs.next() method is ski

Answer 1

First, stop building SQL like that - use parameterized SQL and a PreparedStatement. Your current code is vulnerable to SQL injection attacks.

Basically, don't call rs.next() twice in a row (first in the if then in the while)... you can easily do that by converting your while loop into a do/while loop:

if (rs.next()) {
    do {
        System.out.print(rs.getString("idUser") + " ,");
        System.out.print(rs.getString("Name") + " ,");
        System.out.print(rs.getString("Email") + " ,");
        System.out.println(rs.getString("country") + " .");
    } while (rs.next());
}

Or just have the while loop, with a separate variable to detect that you've seen some results:

bool anyResults = false;
while (rs.next()) {
    anyResults = true;
    System.out.print(rs.getString("idUser") + " ,");
    System.out.print(rs.getString("Name") + " ,");
    System.out.print(rs.getString("Email") + " ,");
    System.out.println(rs.getString("country") + " .");
}
if (!anyResults) {
    JOptionPane.showMessageDialog(null, "Not Found");
}

(Additionally, you should use try-with-resources to close your ResultSet etc, and just printing a stack trace to stdout is almost never the appropriate way to handle exceptions...)