What is the Problem With This Code?

I wrote a JavaBean to interface with another third party application but I am having the error below:

Caused by: java.util.NoSuchElementException
at java.util.HashMap$HashIterator.nextEntry(HashMap.j ava:796)
at java.util.HashMap$KeyIterator.next(HashMap.java:82 8)
at voiceexpert.DiagnosingEngine.execute(DiagnosingEng ine.java:33)
at voiceexpert.Symptoms.process(Symptoms.java:57)
... 21 more
I think the problem is in the "DiagnosingEngine" class, especially tne portion below:

// Return the Disease diagnosed
return (Disease) engine.getObjects(new Filter.ByClass(Disease.class)).next();

I need your assistance please!

The whole code is as below:

Code Java:

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package voiceexpert;
 
import java.io.Serializable;
 
/**
 *
 * @author Oyelami
 */
public class Symptoms implements Serializable{
    private String s1, s2, s3, result;
    private Disease diseaseobject;
 
    public void setS1(String symptom1)
    {
        this.s1=symptom1;
    }
 
    public void setS2(String symptom2)
    {
        this.s2=symptom2;
    }
    public void setS3(String symptom3)
    {
        this.s3=symptom3;
    }
   public Symptoms()
    {
 
    }
   public Symptoms(String symptom1, String symptom2,String symptom3)
   {
       s1=symptom1;
       s2=symptom2;
       s3=symptom3;
 
   }
   public String getS1()
   {
       return s1;
   }
 
   public String getS2()
   {
       return s2;
   }
 
   public String getS3()
   {
       return s3;
   }
 
 
   public String process()
    {
    DiagnosingEngine engine = new DiagnosingEngine(s1,s2,s3);
    diseaseobject=engine.execute();
    result = diseaseobject.diagnosis;
    return result;
    }
 
 
   public String getResult()
   {
       return result;
   }
 
}// end of class Symptoms

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Code Java:

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package voiceexpert;
 
public class Disease {
    public String diagnosis;
    public Disease(String thediagnosis)
    {
        diagnosis=thediagnosis;
    }
 
}
 
 
package voiceexpert;
import jess.JessException;
import jess.*;
 
 
public class DiagnosingEngine {
    private Rete engine;
    private WorkingMemoryMarker marker;
    public DiagnosingEngine(String symptom1, String symptom2, String symptom3)
    {
        try{
        // create a Jess rule engine
        engine = new Rete();
        engine.reset();
        //Load the rules
        engine.batch("diagnosingvoice.clp");
        // Create a new Symptom object and initialize with the syptoms supplied by the caller
        Symptoms s =new Symptoms(symptom1, symptom2, symptom3);
        // Load the symptoms into the working memory
        engine.add(s);
        // mArk the end of symptoms for later
        marker = engine.mark();
    } catch(JessException e){}
    }
 
    public Disease execute()
    {
        try{
      // Fire the rules that apply to those symptoms
        engine.run();
            } catch (JessException e){}
 // Return the Disease diagnosed
        return (Disease) engine.getObjects(new Filter.ByClass(Disease.class)).next();
    }
 
}// end of class DiagnosingEngine

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Please, can somebody help me out?

Quote:

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Please, can somebody help me out?

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Probably not with the information you provided...the exception points you to the exact line of code where the error is occurring (returning the diagnosed disease) as well as what is happening (trying to get something from a Map that isn't there). Beyond that, since we don't what Rete is, we can't barely even guess