Java bridge to octave

Question

: why the file.txt is not created?
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.Scanner;
public class BridgeToOctave {
    //jMatrix the normalized matrix
    public static double[][] imageReshape(double[][] normalizedMatrix, int sameHeight, int sameWidth)
        StringBuilder octaveCommands =
                createOctaveCommand(normalizedMatrix, sameHeight, sameWidth);
        System.out.println("octave command created");
        executeViaTerminal(octaveCommands);
        System.out.println("octave command executed");
        double[][] reshapedM = readFile(sameHeight, sameWidth);
        if(reshapedM == null){
            System.err.println("Null matrix! ERROR");
            System.exit(1);
        System.out.println("the reshaped matrix was loaded");
        return(reshapedM);
    } //end of method
    private static StringBuilder createOctaveCommand(double[][] normalizedMatrix, int sameHeight, int sameWidth){
        StringBuilder octaveCommands = new StringBuilder("A=[");
        try{
            int rows = normalizedMatrix.length;
            int cols = normalizedMatrix[0].length;
             //System.out.println("rows = " + rows);
             //System.out.println("width = " + cols );
             rows = rows - 1;
             cols = cols -1;
            //read the normalized matrix
             //System.out.println("Reading the normalized matrix");
             for(int i=0; i< rows; i++){
                 for(int j=0; j< cols; j++ ){
                     octaveCommands.append(normalizedMatrix[i][j] + " ");
                 octaveCommands.append(";");
            octaveCommands.append("];");
            //now lets call the imresize function via octave
            octaveCommands.append(" resizedA = imresize(A, [" +
                    sameHeight + " " + sameWidth +
                    "]" + "," + "'bicubic'); ");
            //and then save that resized image as an array, in fileTxt.txt
            octaveCommands.append("save ('-text', '/home/elias85/file.txt', 'resizedA');");
            return(octaveCommands);
        }catch(Exception e){
            e.printStackTrace();
            return(null);
    private static void executeViaTerminal(StringBuilder octaveCommands){
        BufferedWriter out;
        try {
            out = new BufferedWriter(new FileWriter(new File("/home/elias85/commands.m")));
            //now parse the octave commands to the commandsMFile.m fileTxt
            out.write(octaveCommands.toString());
            //System.out.println("wrote commands to file");
            out.close();
            //now lets EXECUTE this fileTxt with octave
            Runtime r = Runtime.getRuntime();
            String cmd[] = { "/usr/bin/octave", " /home/elias85/commands.m"};
            //System.out.println("> octave /home/elias85/commands.m");
            Process p = r.exec(cmd);
            r.gc();
            p.destroy();
        } catch (IOException ex) {
            ex.printStackTrace();
    private static double[][] readFile(int sameHeight, int sameWidth){
        try{
                  File fileTxt = new File("/home/elias85/file.txt");
                  // Create a scanner to read the fileTxt
                  //System.out.println("creating scanner");
                  Scanner scanner = new Scanner (fileTxt);
                  //String unused = null;
                  //System.out.println("About to ignore the 1st 5 lines");
                  for(int i =0; i< 5; i++) //5 comment lines in the octave saved fileTxt
                      /*unused  += */scanner.nextLine();
                  //System.out.println("unused string = " + unused);
                  double[][] reshapedM = new double[sameHeight][sameWidth];
                  DecimalFormat df = new DecimalFormat("#.#####");
                  for(int i=0; i<sameHeight; i++){
                      for(int j=0; j<sameWidth; j++){
                          reshapedM[i][j] = Double.parseDouble(df.format(scanner.nextFloat()));
                  fileTxt.delete();
                  scanner.close();  //close the scanner
                  return(reshapedM);
              }catch(Exception e){
                  e.printStackTrace();
                  return(null);
} //end of classthis is a Java-Octave bridge. Even though it seems working, when it executes it can't find the file.txt file.why is that? i tell octave to save to file.txt file.when I do the same using the linux console then the file.txt is created fine

Answer 1

You cannot delete a file which which is open. Close the scanner before attempting to delete the file.
when it executes it can't find the file.txt file.why is that?Try checking that txtFile.exists() and txtFile.canRead()
What is the exact exception?