A question on a Swing design component. Please see

Question

Folks,
Please no offence meant.
If you are creating a new class in eclipse you are displayed the New Java class dialog.
Correct?
New Java Class
  Create a new Java class
Source folder  [     ]
Package:       [     ]If you click on the text field in Package:,there appears a small light bulb pops up on the left hand side of the text field.
Does anyone have any idea what this decorator is called and how can this be achieved using plain Java Swing
I would like to employ this same concept if a user enter a value in a Text Field and a small bulb appears....

Answer 1

That's just a label with a tooltip, probably with its visibility triggered on focus gained.
Something like (simplified):
    JLabel lab = new JLabel(lightbulbImageIcon);
    lab.setTooltip("Content assist available");
    lab.setVisible(false);
    JTextField editingField = ...;
    editingField.addFocusListener(){
        new FocusListener(){
            @Override
            public void focusGained(FocusEvent e){
                if( ContentAssitstManager.isContentAssistAvailable(e.getSource()) ){
                    label.setVisible(true);
            @Override
            public void focusLost(FocusEvent e){
                label.setVisible(false);
    };