SETTING FIELD IN ANOTHER CLASS

[eh171]

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