Why this program can not succeed ah

import java.applet. *;
import java.awt. *;
import java.awt.event. *;
public class leapyear extends Applet implements ActionListener
{
Label result;
TextField inl;
Button btn;
int year;
boolean leap;
public void init ()
{
result = new Label (" Please enter the number to determine the year " ) ;
inl = new TextField (5);
add (inl);
add (btn);
add (result);
btn.addActionListener (this);
}
public void actionPerformed (ActionEvent e)
{
year = Integer.parseInt (inl.getText ());
if (year% 4! = 0)
leap = false;
else if (year% 100! = 0)
leap = true;
else if (year% 400! = 0)
leap = false;
else
leap = true;
if (leap == true)
result.setText (year + " is a leap year " ) ;
else
result.setText (year + " not a leap year " ) ;
inl.setText ("");
}
}

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understand java -based Friends of the roof to help
estimate is junk code
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class name initials why is lowercase ?


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In addition, this program where you are unsuccessful up ?
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said no public static void main (String arg []) can not run the main method . . . .  

public static void main ( String [] args )
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white excited. . . I thought I solved it
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said no public static void main (String arg []) can not run the main method . . . .
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I tried . . . I still ah
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said no public static void main (String arg []) can not run the main method . . . .
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to a main method .