Java Leap Year test and resolve illegal input

Problem implementation

The Java code that implements a leap year test is as follows:

 Packageleapyear;Importjava.awt.event.ActionEvent;ImportJava.awt.event.ActionListener;ImportJavax.swing.JButton;ImportJavax.swing.JFrame;ImportJavax.swing.JLabel;ImportJavax.swing.JPanel;ImportJavax.swing.JTextField; Public classLeapyearextendsJFrameImplementsactionlistener{PrivateJTextField textfield=NULL; PrivateJButton btn;  Publicleapyear () {JFrame F=NewJFrame ("Leap year"); JPanel P=NewJPanel (); TextField=NewJTextField ("", 10); JButton btn=NewJButton ("OK"); JLabel Label1=NewJLabel ("Input"); Btn.addactionlistener ( This);        P.add (Label1);        P.add (TextField);        P.add (BTN);        F.add (P); F.setvisible (true);        F.setdefaultcloseoperation (Jframe.exit_on_close); F.setsize (300, 200); F.setbounds (150,150,150,150);        F.pack (); }         Public voidactionperformed (ActionEvent e) {String F; F=Textfield.gettext (); String Q=""; Try{                intP1 =Integer.parseint (f); if(Checkleap (p1)) {Q= "This is a leap year!"; }                Else{Q= "This is not a leap year!"; }            }            Catch(NumberFormatException s) {Q= "Illegal input!";        } textfield.settext (q); }         PublicBoolean Checkleap (intYear ) {Boolean temp=false; if(year% 4 = = 0) {Temp=true; }            if(year% 100 = = 0) {Temp=false; }            if(Year% 400 = = 0) {Temp=true; }            returntemp; }          Public Static voidMain (string[] args) {Newleapyear (); }    }

The code's algorithm is simple to understand, in the restriction illegal operation, I use the Try,catch method to determine whether the input is a number, if not the number then obtains an error message.

Test Cases

Test Cases	Expected output	Actual output
1234	This is not a leap year!	This is not a leap year!
2000	This is a leap year!	This is a leap year!
1000	This is not a leap year!	This is not a leap year!
Abcd	Illegal input!	Illegal input!
#￥&	Illegal input!	Illegal input!

Test

Java Leap Year test and resolve illegal input