can't solve this error with json object
<p>i write this code to read json data , and there is an error when run the code </p>

<p>first this is the code i write ( i changed the code to correct the json string but the problem still exist )</p>

<pre><code>import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;

public class defaults {

    public static void main(String[] args) {
        String jsonTxt = "{lhs: \"100 Euros\",rhs: \"128.551738 Australian dollars\",error: \"\",icc: true}";        
         JSONObject json = (JSONObject) JSONSerializer.toJSON( jsonTxt );
        String title = json.getString("title");               
        System.out.println( "title: " + title );
    }
}
</code></pre>

<p>and i have found this error when run the code </p>

<pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source).....
</code></pre>

<p>the error gone away if i remove lines that talks about json </p>
