speech recognition in java

Question

I want to use speech recognition in my project and I found this code but when I run it I get an error which is:

run: java.lang.NullPointerException
        at newpackage.HelloWorld.main(HelloWorld.java:55)

Please could one of you help me in this problem?

This is the server code that I use:

package newpackage;

import java.util.logging.Level;
import java.util.logging.Logger;
import javax.speech.*;
import javax.speech.recognition.*;
import java.io.FileReader;
import java.util.Locale;

public class HelloWorld extends ResultAdapter {
  static Recognizer rec;

  // Receives RESULT_ACCEPTED event: print it, clean up, exit
  public void resultAccepted(ResultEvent e) {
    Result r = (Result)(e.getSource());
    ResultToken tokens[] = r.getBestTokens();

    for (int i = 0; i < tokens.length; i++)
      System.out.print(tokens[i].getSpokenText() + " ");

    System.out.println();
    try {
          // Deallocate the recognizer and exit
          rec.deallocate();
    } catch (EngineException ex) {
          Logger.getLogger(HelloWorld.class.getName()).log(Level.SEVERE, null, ex);
    } catch (EngineStateError ex) {
          Logger.getLogger(HelloWorld.class.getName()).log(Level.SEVERE, null, ex);
    }
    System.exit(0);
  }

  public static void main(String args[]) {
    try {
      // Create a recognizer that supports English.
      rec = Central.createRecognizer(
              new EngineModeDesc(Locale.ENGLISH));

      // Start up the recognizer
      rec.allocate();

      // Load the grammar from a file, and enable it
      FileReader reader = new FileReader(args[0]);
      RuleGrammar gram = rec.loadJSGF(reader);

      gram.setEnabled(true);

      // Add the listener to get results
      rec.addResultListener(new HelloWorld());

      // Commit the grammar
      rec.commitChanges();

      // Request focus and start listening
      rec.requestFocus();
      rec.resume();
    } catch (Exception e) {
      e.printStackTrace();
          // System.out.println("the problem");
    }
  }
}

Answer 1

if (rec != null) {
    System.out.println(rec);
}
else {
    System.out.println("rec is null");   
    // <-- here's your problem.  you need to return, exit, or throw here!
}

// Start up the recognizer
rec.allocate();  // <-- This is the line that's blowing out (I assume)

You'll get a null pointer because even though your else is handling the case when rec is null, your program continues. You need to return or exit, or something when rec is null.

Note: Also, I reformatted your code because it's hard to read your if/else. If you're going to use curlies on one branch of your if/else, you should use curlies on both. It makes it more readable.

Edit: Oh yeah, as far as why createRecognizer is returning null, I'm afraid I don't know.

Answer 2

rewrite the

// Create a recognizer that supports English.
      rec = Central.createRecognizer(
              new EngineModeDesc(Locale.ENGLISH));

to be as below

            SynthesizerModeDesc desc = new SynthesizerModeDesc(
            null,          // engine name
            "general",     // mode name
            Locale.US,     // locale
            null,          // running
            null);         // voice

     synth = Central.createSynthesizer(desc);