java.awt.CheckboxGroupCheckboxGroup are often called radio buttons. Checkboxes that are members of the same CheckboxGroup cannot be checked simultaneously. When the user checks one, all others are unchecked automatically.
The constructor for a CheckboxGroup is trivial. No arguments are needed. You do not even need to add the CheckboxGroup to the applet since checkbox groups are themselves not user-interface widgets, just ways of arranging checkboxes.
CheckboxGroup cbg = new CheckboxGroup();
To make check boxes act like radio buttons, use this constructor
Checkbox(String label, CheckboxGroup cbg, boolean checked)
for each Checkbox in the group. The label is the label for this Checkbox. The CheckboxGroup is the group you want this Checkbox to belong to and must already exist.
At any time, you can get or set the selected Checkbox with these two methods:
public Checkbox getSelectedCheckbox()
public synchronized void setSelectedCheckbox(Checkbox box)