SETTING FIELD IN ANOTHER CLASS

Question

I have 3 classes: class1 extends Jpanel, class2 extends Jpanel, class3 extends JFrame. What I am trying to do is set the textfields in class1 from class2 according to user input: user enters an ID and presses a button (in another frame: class4) and data relating to that ID e.g. name, number... is retrieved from the server and then the fields in class1 are set to these values from class2. I have the following coding
class 1
JTextfield nameField = new JTextField()
class1 constructor(
panel.add(nameField)
class2
class1 c1 = new class1()
c1.clTextField.setText(...)
panel.add(c1)
class 3 constructor
panel.add(class2Object);
when the user enters an ID (in class4)and presses enter the correct data is displayed. However when I close down the class3 frame and enter another ID the frame gets displayed but all the textFields have gone missing????????
p.s. what is the difference between creating a new object and invoking it on the textfield e.g.(in class1)
class2 c2 = new class2
c2.textFieldInClass2
and stating the textfield as a static string in class2 and then just invoking class2Name on it in class1 e.g.
class2Name.textfield

Answer 1

import java.util.Date;
public class Time {
SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss")
Date utilDate;
java.sql.TimeStamp sqlDate;
String stringDate;
public Time(){
utilDate = new Date();
stringDate = formatter.format(utilDate)
sqlDate = new java.sql.TimeStamp(utilDate.getTime)
stringDate can be displayed in frame. sqlDate is entered into the server. you can have the simpledateformat according to the format date you require