Strange symbols when using byte-based FileOutputStream, char-based FileWriter is OK

Question

Task :

Write a Java application that creates a file on your local file system which contains 10000 randomly generated integer values between 0 and 100000. Try this first using a byte-based stream and then instead by using a char-based stream. Compare the file sizes created by the two different approaches.

I made the byte-based stream. After I run this program, in fileOutput I get some weird symbols. Am I doing something wrong ?

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Random;

public class Bytebased {

    public static void main(String[] args) throws IOException {

    File outFile = new File( "fileOutput.txt" );
    FileOutputStream fos = new FileOutputStream(outFile);

    Random rand = new Random();
    int x;

    for(int i=1;i<=10001;i++){
         x = rand.nextInt(10001);
        fos.write(x);
    }
    fos.close();
    }
}

When I'm using char-based stream it works:

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Random;

public class Charbased {

    public static void main(String[] args) throws IOException {

    File outFile = new File( "fileOutput2.txt" );
    FileWriter fw = new FileWriter(outFile);

    Random rand = new Random();
    int x;
    String y;
    for(int i=1;i<=10001;i++){
         x = rand.nextInt(10001);
         y=x + " ";
         fw.write(y);
    }

    fw.close();

    }
}

Answer 1

Writing a regular output to a file directly from a FileOutputSream will do that, you need to convert your output into bytes first. Something like :

public static void main(String[] args) throws IOException {

    File outFile = new File( "fileOutput.txt" );
    FileOutputStream fos = new FileOutputStream(outFile);

    String numbers = "";

    Random rand = new Random();

    for(int i=1;i<=10001;i++){
        numbers += rand.nextInt(10001);
    }

    byte[] bytesArray = numbers.getBytes();
    fos.write(bytesArray);
    fos.flush();
    fos.close();
}