New to Java, need assistance

Question

First, I'd like to apologize in case this post is in the wrong place.
Now I'm new to Jcreator and I missed about a month from my computer programming class in school, and am far behind. My assignment right now is this problem p5.12 from Computing Concepts with Java Essentials it says:
"A year with 366 days is called a leap year. A year is a leap year if it is divisible by 4 (for ex.,1980). However, since the introduction of the Gregorian calender on October 15, 1582, a year is not a leap year if it is divisible by 100 (for ex., 1900); however, it is a leap year if it is divisible by 400 (for ex., 2000). Write a program that asks the user for a year and computes whether that year is a leap year., Implement a class *Year* with the method *boolean isLeapYear*
This is the code that I came up with:
import javax.swing.JOptionPane;
public class LeapYear {
     public static void main(String[] args) {
          String input = JOptionPane.showInputDialog("Enter Year");
          double year = Double.parseDouble(input);
          LeapYear newYear = new LeapYear(year);
          System.out.println(newYear.boolean isLeapYear()); //line 11
public class LeapYear {
     private double year;     
     public LeapYear(double year)
               a = year;
          public boolean isLeapYear(){
               if(a % 4 == 0)
                         if(a % 100 != 0) System.out.println("Leap Year");
               else if (a % 400 == 0) System.out.println("Leap Year");
               else System.out.println("Not Leap Year");
The error I am receiving is on the 11th line of the test class. I know if there is something wrong besides that. I'm not asking for someone to fix this for me but I would like if somebody could give me advice on what to do, hints, explain where I went wrong, or know of any good tutorials I could read that could help me with this it would be much appreciated.

Answer 1

Year           Is Leab Year?
1           no      
4            yes
1580            yes
1582           no      
1584            yes      
1600            yes      
1700            no      
1800            no      
1900            no      
1996            yes      
1997           no      
1999            no      
2000            yes      
2100            no      
2200            no      
2300            no      
2400            yes      
2800            yes      
2900            no      
3200            yes      
3300            no      
3600            yes      
3800            no      
4000            yes      
4200            no      
4400            yes      
4700            no      
4800            yes      
5100            no      
5200            yes      
6400            yes      
6500            no      
6800            yes      
6900            no      
7200            yes      
7400            no      
7600            yes      
7800            no