JSON Decoding help

I got the .jar from json-simple - JSON.simple - A simple Java toolkit for JSON - Google Project Hosting that I added to my Java build path in eclipse. The example works and now I am trying to decode a JSON object from https://mtgox.com/api/0/data/ticker.php but I get an error : Exception in thread "main" java.lang.NullPointerException
at mtgox.main(mtgox.java:45). Thanks for you help my code is posted below:
I changed it back to the example to did compile correctly, but my problem is when i add the line variable to replace string s.

Code :

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		import java.io.BufferedReader;
		import java.io.IOException;
		import java.io.InputStreamReader;
		import java.util.ArrayList;
		import java.util.List;
 
		import org.apache.http.HttpResponse;
		import org.apache.http.NameValuePair;
		import org.apache.http.client.HttpClient;
		import org.apache.http.client.entity.UrlEncodedFormEntity;
		import org.apache.http.client.methods.HttpPost;
		import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
 
		public class mtgox { 
			public static void main(String[] args) {
				HttpClient client = new DefaultHttpClient();
				HttpPost post = new HttpPost("https://mtgox.com/api/0/data/ticker.php");
				try {
					List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
					nameValuePairs.add(new BasicNameValuePair("registrationid",
							"123456789"));
					post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
 
					HttpResponse response = client.execute(post);
					BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
					String line = "";
					while ((line = rd.readLine()) != null) {
						System.out.println(line);
					}
 
				} catch (IOException e) {
					e.printStackTrace();
				}
 
				  System.out.println("=======decode=======");
 
				  String s="[0,{\"1\":{\"2\":{\"3\":{\"4\":[5,{\"6\":7}]}}}}]";
				  Object obj=JSONValue.parse(s);
				  JSONArray array=(JSONArray)obj;
				  System.out.println("======the 2nd element of array======");
				  System.out.println(array.get(1));
				  System.out.println();
 
				  JSONObject obj2=(JSONObject)array.get(1);
				  System.out.println("======field \"1\"==========");
				  System.out.println(obj2.get("1"));    
 
 
				  s="{}";
				  obj=JSONValue.parse(s);
				  System.out.println(obj);
 
				  s="[1,]";
				  obj=JSONValue.parse(s);
				  System.out.println(obj);
 
				  s="[5,,2]";
				  obj=JSONValue.parse(s);
				  System.out.println(obj);
			}
 
 
	}

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Quote:

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Exception in thread "main" java.lang.NullPointerException
at mtgox.main(mtgox.java:45).

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Look at line 45 in the your source and see what variable is null. Then backtrack in the code to see why that variable does not have a valid value.
If you can not tell which variable it is, add a println just before line 45 and print out the values of all the varibles on that line.

It is saying that my line variable is null when I try to decode it, but when I do println it prints out the whole JSON object and I only need the "high" and "low".

Quote:

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It is saying that my line variable is null

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Can you post the source line that you are talking about? line 45 where the NPE occurred.

Quote:

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I do println it prints out the whole JSON object

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The variable: line is defined as a String. How does an object get printed? I'd expect to see the content of the line variable which would be a String.