What is the code to clear all the" radio buttons​ " in NETBEANS JAVA ☺☺☺☺

Question

I'm working on a code having 3 radio buttons r1 , r2 and r3,1 text feild t1 and 3 buttons to calculate, clear and exit the code respectively.codes of each buttons are as follows:
CALCULATE BUTTON
double i=0;
if(r1.isSelected())
i=12;
else
if(r2.isSelected())
i=10;
else
if(r3.isSelected())
i=9.5;
t1.setText(" "+I);

CLEAR BUTTON:
r1.setSelected(false);
r2.setSelected(false);
r3.setSelected(false);
t1.setText(" ");

EXIT BUTTON:
System.exit(0);

Answer 1

If you have used buttonGroup1 to bind them together to accept single selection than you should use
buttonGroup1.clearSelection();
method to clear them.

Answer 2

can you please explain it in more detail????