$//$ Java Program to Implement Traffic signal$//$ Using Java Swing Components$//$ Importing required classesimport java.awt.$*$;import java.awt.event.$*$;import java.util.$*$;import javax.swing.$*$;$//$ Main class$//$ Extending JFrame class and$//$ Implementing ItemListener interfacepublic class Traffic$\_$Signalextends JFrame implements ItemListener $\{//$ Setting the buttons for the layoutJRadioButton jr$1$;JRadioButton jr$2$;JRadioButton jr$3$;$//$ Setting the field areaJTextField j$1=$ new JTextField$(10)$;ButtonGroup b $=$ new ButtonGroup$()$;String msg $=""$;$//$ Initially setting the co$-$ordinates to $0,0,0$int x $=0,$ y $=0,$ z $=0$;public Traffic$\_$Signal$($String msg$)\{$super$($msg$)$;setLayout$($new FlowLayout$())$;$//$ Assigning name to the button declared above$//$ with help of JRadioButton classjr$1=$ new JRadioButton$("$Red$")$;jr$2=$ new JRadioButton$("$Yellow$")$;jr$3=$ new JRadioButton$("$Green$")$;jr$1.$addItemListener$($this$)$;jr$2.$addItemListener$($this$)$;jr$3.$addItemListener$($this$)$;add$($jr$1)$;add$($jr$2)$;add$($jr$3)$;b$.$add$($jr$1)$;b$.$add$($jr$2)$;b$.$add$($jr$3)$;add$($j$1)$;$//$ Method $1//$ To add a windowaddWindowListener$($new WindowAdapter$()\{$public void windowClosing$($WindowEvent e$)\{//$ It haults here itselfSystem.exit$(0)$;$\}\})$;$\}//$ Method $2//$ To change colors of traffic signalpublic void itemStateChanged$($ItemEvent ie$)\{//$ If it is redif $($ie$.$getSource$()==$ jr$1)\{$if $($ie$.$getStateChange$()==1)\{//$ Then display message$-$ Stopmsg $=$ "Stop!";x $=1$;$//$ Repainting the box with original one$//$ Practically blackrepaint$()$;$\}$else $\{$msg $=""$;$\}\}//$ If state is Orange or technically jr$2$if $($ie$.$getSource$()==$ jr$2)\{$if $($ie$.$getStateChange$()==1)\{//$ Then display message$-//$ Get ready in waiting statemsg $=$ "Get Ready to go$!"$;y $=1$;$//$ Again repainting the buttonrepaint$()$;$\}$else $\{$msg $=""$;$\}\}//$ If state is Greenif $($ie$.$getSource$()==$ jr$3)\{$if $($ie$.$getStateChange$()==1)\{//$ Then display message$-$ Gomsg $="$Go$!!"$;z $=1$;repaint$()$;$\}$else $\{$msg $=""$;$\}\}$j$1.$setText$($msg$)$;$\}//$ Method $3//$ handling the paint graphics and$//$ dimensions of the buttons via$//$ setting co$-$ordinatespublic void paint$($Graphics g$)\{$g$.$drawRect$(100,105,110,270)$;g$.$drawOval$(120,150,60,60)$;g$.$drawOval$(120,230,60,60)$;g$.$drawOval$(120,300,60,60)$;$//$ Case: Redif $($x $==1)\{$g$.$setColor$($Color$.$RED$)$;g$.$fillOval$(120,150,60,60)$;g$.$setColor$($Color$.$WHITE$)$;g$.$fillOval$(120,230,60,60)$;g$.$setColor$($Color$.$WHITE$)$;g$.$fillOval$(120,300,60,60)$;x $=0$;$\}//$ Case: Orangeif $($y $==1)\{$g$.$setColor$($Color$.$WHITE$)$;g$.$fillOval$(120,150,60,60)$;g$.$setColor$($Color$.$YELLOW$)$;g$.$fillOval$(120,230,60,60)$;g$.$setColor$($Color$.$WHITE$)$;g$.$fillOval$(120,300,60,60)$;y $=0$;$\}//$ Case: Greenif $($z $==1)\{$g$.$setColor$($Color$.$WHITE$)$;g$.$fillOval$(120,150,60,60)$;g$.$setColor$($Color$.$WHITE$)$;g$.$fillOval$(120,230,60,60)$;g$.$setColor$($Color$.$GREEN$)$;g$.$fillOval$(120,300,60,60)$;z $=0$;$\}\}//$ Method $4//$ Main driver methodpublic static void main$($String args$[])\{//$ Creating object of Jframe class inside main$()//$ methodJFrame jf $=$ new Traffic$\_$Signal$("$Traffic Light"$)$;$//$ Setting size and making traffic signal$//$ operational using setVisible$()$ methodjf.setSize$(500,500)$;jf$.$setVisible$($true$)$;$\}\}$

Project $1$: Add $2$ more lights to the traffic signal. Explain what you did and how you did it$.$