PostgreSQL JDBC

I seem to be having some problems w/ the psql jdbc driver. I'm able to load the driver, but as soon as I try to connect w/ the database. here's my code:

import java.sql.*;

public class dataBase {
public static void main(String [] args){
try {
Class.forName("org.postgresql.DriverClass").newInstance();
System.out.println("Driver Loaded Successfully");
} catch (Exception e) {
System.out.println("Unable to Load Driver " + e.getMessage() );
}
try {
Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost/mapping",
"mapping", "");
} catch (SQLException e) {
System.out.println("SQLException: " + e.getMessage());
}
}
}

When I run this code as shown, I get the following output:
Driver Loaded Successfully
SQLException: No suitable driver

I'm trying to connect to the database "mapping" under the user "mapping" w/ no password. Does anybody know what I'm doing wrong? I'm running psql ver 7.0.2 and jdbc driver "jdbc7.0-1.2.jar" and the java 1.3 jdk. Any comments or suggestions would be greatly appreciated. thanks.