Cannot Run File b/c of Parsing

[lilk132z]

I am trying to create an applet for people to enter information, and the program should return a certain stat.

However, after the user inputs all of the necessary information, no data is returned but this error message is:

Exception in thread "main" java.lang.NullPointerException
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:991)
at java.lang.Double.parseDouble(Double.java:510)
at Player.toDouble(Player.java:110)
at Player.numSingles(Player.java:115)
at Player.clutchFactor(Player.java:122)
at Test.main(Test.java:19)

The program successfully returns a double when I input data, but it won't return when the user takes the data.

import java.io.*;
public class Test {

    public static void main (String[] args) throws IOException
     {
		System.out.println("Go to sports.yahoo.com/mlb/ and look for situational stats");
		Player a= new Player ("2800", "33", "2", "23", "2", "51", "1", "3", "1", "345");
		Player bigGuy = new Player ();
		System.out.println(a.clutchFactor());
		System.out.println(bigGuy.clutchFactor());
	 }


}

import java.io.*;
import java.*;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;

public class Player {
	public String AB;
	public String HR;
	public String K;
	public String BB;
	public String hits;
	public String dub;
	public String trip;
	public String SB;
	public String CS;
	public String OBP;

	public Player(String a, String h, String k, String b, String hi, String d, String t, String sb, String cs, String obp)
	{
		this.AB = a;
		this.HR = h;
		this.K = k;
		this.BB = b;
		this.hits = hi;
		this.dub = d;
		this.trip = t;
		this.SB =  sb;
		this.CS = cs;
		this.OBP = obp;
	}

    public Player() throws IOException {
        //the data that will be entered by the user
	String AB;
	String hits;
	String dub;
	String trip;
	String HR;
	String BB;
	String K;
	String SB;
	String CS;
	String OBP;

	//what the program will ask to be entered
		StringReader sreader = new StringReader("check");
        BufferedReader reader = new BufferedReader(sreader);

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of At Bats ");
        AB = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of hits ");
        hits = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of doubles ");
        dub = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of triples ");
        trip = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of home runs ");
        HR = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of walks ");
        BB = reader.readLine();


        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of strikeouts ");
        K = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of Steals ");
        SB = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Number of times caught stolen ");
        CS = reader.readLine();

        reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("On base percentage ");
        OBP = reader.readLine();


    }
    //methods

    public static double toDouble(String a)
    {
    	return Double.parseDouble(a);
    }

    public Double numSingles()
    {
    	return toDouble(this.hits)-(toDouble(this.trip)+toDouble(this.dub)+toDouble(this.HR));
    }

    public String clutchFactor()
    {
    	if (1>0) //modify this to be late game and true)
    	{
    		double cfNum = (numSingles()+2*toDouble(this.dub)+3*toDouble(this.trip)+4*toDouble(this.HR)+(toDouble(this.BB)/2));
    		double cfDenom = ((toDouble(this.OBP) + 1)/1000) *(2*toDouble(this.K)+1);
    		double almost = 1000*(cfNum/cfDenom)*((toDouble(this.SB)+1)/(toDouble(this.SB)+toDouble(this.CS)+1));
    		return ("" + almost/toDouble(this.AB));
    	}
    	else
    	{
    		return "Stats must be entered from splits in clutch situations, ie 7th inning and on w/ the score w/in 3";
    	}
    }
}