This Java (jar) application will take a .WAV file
named "input.WAV" and create a file named "output.wav"
The pcm data in the input file is read and each sample value
subtracted from itself - the result is written to
the output.

listing as follows-

package nullpcm;
import java.io.*;
public class nullpcm {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
	
		File file = null;
		File fileo = null;
	        int cnt = 0;
			short sh;

		    // Get the file from the argument line.
		    if (args.length > 0) file = new File (args[0]);
		    if (file == null) {
		      System.out.println ("Default: input.wav");
		      file = new File ("input.wav");
		      fileo = new File ("output.wav");

		      String curDir = System.getProperty("user.dir");
			  System.out.println (curDir);
		    } // end of if for args
	  
		    try {
		    
		      // Wrap the FileInputStream with a DataInputStream
		      FileInputStream file_inputg = new FileInputStream (file);
		      DataInputStream data_get    = new DataInputStream (file_inputg );
		      DataOutputStream output = new DataOutputStream(
	              new FileOutputStream(fileo));
		      //
	              while (true) {
		        try {
		            sh = data_get.readShort();
	                    if (cnt > 42) { sh = (short) (sh - sh) ;}                          
	                    output.writeShort(sh);  
	                    cnt = cnt + 2;
		            } // try
		        catch (EOFException eof) 
	                    {
		            System.out.println ("End of File");
		            break;
		            } // catch
		                   } // while true
		     
		      data_get.close ();
		      output.close();
		      System.out.println (cnt + " bytes of Data Output!");
		    } catch  (IOException e) {
		       System.out.println ( "IO Exception =: " + e );

		} // end of try for file

	}// end public

}// end class