Hashmap issues, getting exception I don't understand
===

I'm getting a nulpointerexception and cant figure out why. I have read a lot of the questions on here and cant seem to disect anything well enough to get the answers i need. im working with a hashmap and im trying to refrence it from a diferant module here is the code:
    
    import java.util.*; 
    @SuppressWarnings("unused")
    public class Decoder 
    {
	public static void main(String[] args)
	{
		decrypt();
		keywork(null);
	}
	
	static void decrypt()
	{
		String codedline = "ilyh wkrxvdqg, wzr kxqguhg dqg qlqhwb-wkuhh".toLowerCase();
		char[] cwarr = codedline.toCharArray();
		String dcline  = "";
		for(char x : cwarr)
		{
			if(Character.isLetter(x))
			{
				int c = (int)x;
				c = c - 3;
				if(c > 90 && c < 97)
				{
					 c += 26;
				}
				x = (char)c;
				dcline += x;
			}else
			{
				dcline += x;
			}
		}
		System.out.println(dcline);
	}
	
	static void keywork(String dcline)
	{
		int x;
		for(int i = 1, sw = 0; i == dcline.length(); i++)
		{
			String strchk = dcline.substring(sw, i);
			Object n = hm.get(strchk);
		};
	}
	
	
	

	static final HashMap<String, Integer> hm = new HashMap <String, Integer>()
	{
	/**
		 * 
		 */
		private static final long serialVersionUID = 2688387173090905196L;
	{
		hm.put("ONE", 1);
		hm.put("TWO", 2);
		hm.put("THREE", 3);
		hm.put("FOUR", 4);
		hm.put("FIVE", 5);
		hm.put("SIX", 6);
		hm.put("SEVEN", 7);
		hm.put("EIGHT", 8);
		hm.put("NINE", 9);
		hm.put("TEN", 10);
		hm.put("ELEVEN", 11);
		hm.put("TWELVE", 12);
		hm.put("THIRTEEN", 13);
		hm.put("FOURTEEN", 14);
		hm.put("FIFTEEN", 15);
		hm.put("SIXTEEN", 16);
		hm.put("SEVENTEEN", 17);
		hm.put("EIGHTEEN", 18);
		hm.put("NINETEEN", 19);
		hm.put("TWENTY", 20);
		hm.put("THIRTY", 30);
		hm.put("FOURTY", 40);
		hm.put("FIFTY", 50);
		hm.put("SIXTY", 60);
		hm.put("SEVENTY", 70);
		hm.put("EIGHTY", 80);
		hm.put("NINETY", 90);
		hm.put("HUNDRED", 100);
		hm.put("THOUSAND", 1000);
	}
	};
    }    


this is what im getting:

    java.lang.ExceptionInInitializerError
    Caused by: java.lang.NullPointerException
	at Decoder$1.<init>(Decoder.java:56)
	at Decoder.<clinit>(Decoder.java:49)
    Exception in thread "main" 