Components & Properties

Java graphical elements are based on the Composite design pattern and are divided into "basic" components (Button, Label, TextField, etc.) and "composite" (Frame or Panel for instance) with fundamentaly an "add" operation to add recursively other basic/composite components.
Each component is characterized by "properties" specified with getter/setter (and have to be distinguished with attributes).

JFrame     frame  = new JFrame("Demo1");
JPanel     panel  = new JPanel();
JLabel     label  = new JLabel("Your name:");
JTextField name   = new JTextField(10);
JButton    button = new JButton("Validate");

panel.add(label);
panel.add(name);
frame.add(panel);
frame.add(button);
frame.setLayout(new GridLayout(2,1));
frame.pack();
frame.setVisible(true);

source

As an exercise, draw the tree structure of the User Interface (UI) by the way of an objects' diagram.