writing to a file problem

Question

I am using this code to write to a file in java. it has always worked and I am 100% sure its right. But still the file does not get written. I don't even get an error.

import java.io.BufferedWriter;   
import java.io.FileWriter;
import java.io.IOException;

public class writetofile {

    public static void main(String [] args){

        FileWriter fw;

        try {
            fw = new FileWriter("testfile.txt");

            BufferedWriter bw = new BufferedWriter(fw);

            bw.write("this is test");

            bw.write("this is test");
            bw.write("this is test");


        } catch (IOException e) {

            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}

Could it be some other problem?

Answer 1

try fw.flush() and fw.close()

Answer 2

You are not calling the close() method on the BufferedWriter object. That means the buffers never get flushed. Add bw.close() after your last bw.write() statements.

Answer 3

Make sure you call bw.close() before your method exits. If the buffer doesn't get flushed your file wont get written.

Answer 4

Try closing the stream with sw.close() or the data may still be cached and not actually written to disk.

Answer 5

You need to flush the buffer and you should close the file as well:

try {
            fw = new FileWriter("/tmp/testfile.txt");
            BufferedWriter bw = new BufferedWriter(fw);
            bw.write("this is test");
            bw.write("this is test");
            bw.write("this is test");
            bw.flush();
            fw.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

Also you should handle the IOException from the actual file writing separately from the file closing so you won't leave the file descriptor opened at the end:

    FileWriter fw = null;
    try {
        fw = new FileWriter("/tmp/testfile.txt");
        BufferedWriter bw = new BufferedWriter(fw);
        bw.write("this is test");
        bw.write("this is test");
        bw.write("this is test");
        bw.flush();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            if (fw != null) {
                fw.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }