如何让我的程序在JtextField中显示数据库中的用户名？

I'm making a program where you login and it takes you into a into a different frame after you log in.. That part of the program works, but I'm having trouble getting it to return the user's name and other data from the database. It connects to the database, but it won't return the information inside JTextField. If I can find out how to do firstName, I can figure out the rest. I'm using Eclipse as my IDE and SQLite Manager as the database. There are 2 tables Login (username,password) Student(SID,firstName,GradeLevel, and more) Also username is there ID start with an S (like S01 and so forth). Here's the code.I'm making a program where you login and it tak