HELP NEEDED! Not Equal problem!!

Question

Hi, I had written a page that does some validation and in the end if validation are done, insert records into the database.
However I am not sure why my not equals is not working, therfore not inserting records into the database.
WOuld appreciate if anyone can help me out.
     if(event.getSource() == RegisterButton)
               String user;
               //Get username and pwd
               user=txtusername.getText();
               String pass1=new String(txtpassword1.getPassword());
               String pass2=new String(txtpassword2.getPassword());
          if(user.equals("")||pass1.equals("")||pass2.equals("")) {
          JOptionPane.showMessageDialog (this, "Please entered all the fields");
          else if(!pass1.equals(pass2)) {
           JOptionPane.showMessageDialog (this, "Password does not match");
          //Connecting to database for retrival
               String data = "jdbc:mysql://localhost:3306/mydatabase";
               try {
               Class.forName("com.mysql.jdbc.Driver");
               Connection conn = DriverManager.getConnection(data, "root", "admin");
               Statement st = conn.createStatement();
               ResultSet rec = st.executeQuery("SELECT * FROM userInfo WHERE userID='" +user+"' ");
               while(rec.next()) {
               String users = rec.getString("userID");
                System.out.println(users);
                if(user.equals(users)) {
                JOptionPane.showMessageDialog (this, "Please enter a new username");
               if(!user.equals(users)) {
               st.executeUpdate("INSERT INTO userInfo VALUES (user,pass1)");
               st.close();
               catch (SQLException s) {
               System.out.println("SQL Error: " + s.toString() + " "+ s.getErrorCode() + " " + s.getSQLState());
               catch (Exception e) {
               System.out.println(" Error: " + e.toString() + e.getMessage());
               }the part that i highlighted is not working.

Answer 1

i have edited the codes,it insert but doesn't validate 1 of my requirement.
that is when it had the same username,it suppose to prompt user to enter naother new username.
now it inserts duplicate copies of it.
when i insert i also got an erorr saying operation not allowed after result set closed.
can help mi do some editing please.
thanks
     if(event.getSource() == RegisterButton)
               String user;
               //Get username and pwd
               user=txtusername.getText();
               String pass1=new String(txtpassword1.getPassword());
               String pass2=new String(txtpassword2.getPassword());
          if(user.equals("")||pass1.equals("")||pass2.equals("")) {
          JOptionPane.showMessageDialog (this, "Please entered all the fields");
          else if(!pass1.equals(pass2)) {
           JOptionPane.showMessageDialog (this, "Password does not match");
          //Connecting to database for retrival
               String data = "jdbc:mysql://localhost:3306/mydatabase";
               try {
               Class.forName("com.mysql.jdbc.Driver");
               Connection conn = DriverManager.getConnection(data, "root", "admin");
               Statement st = conn.createStatement();
               boolean allow=true;
               ResultSet rec = st.executeQuery("SELECT * FROM userInfo");
               while(rec.next()) {     
               String users = rec.getString("userID");
           //     System.out.println(users);
                if(user.equals(users)) {
                     allow=false;
                JOptionPane.showMessageDialog (this, "Please enter a new username");
               if(allow)  {
               st.executeUpdate("INSERT INTO userInfo VALUES ('"+user+"','"+pass1+"')");
               st.close();
               conn.close();
               catch (SQLException s) {
               System.out.println("SQL Error: " + s.toString() + " "+ s.getErrorCode() + " " + s.getSQLState());
               catch (Exception e) {
               System.out.println(" Error: " + e.toString() + e.getMessage());