BufferedWriter is not writing data properly

Question

What is wrong in the below code? in console it is printing proper data but in file there is no data. it is creating 0-byte file.

 JsonObjectBuilder mainObj= Json.createObjectBuilder();
        mainObj.add("delete",delete);
        mainObj.add("update", update);
        mainObj.add("add",add);
       
        String data = mainObj.build().toString();
        System.out.println(data); **//This line printing output**
        BufferedWriter out = new BufferedWriter(new FileWriter("D:/test.json"));
        out.write(data);

Below output is getting printed to console but it is creating 0-byte file.

{"delete":[{"canonicalName":"Amazon"}],"update":[{"canonicalName":"Infosys"},{"canonicalName":"Google HYD"}],"add":[{"canonicalName":"Apple computers"},{"canonicalName":"Microsoft India"},{"canonicalName":"Amazon"},{"canonicalName":"Google India"},{"canonicalName":"CSC"},{"canonicalName":"INFY"}]}

Try calling `out.close()`, which will flush and close the underlying stream . See : https://docs.oracle.com/javase/8/docs/api/java/io/BufferedWriter.html — Arnaud, Aug 10 '20 at 13:14
As @Arnaud says, you should `.close()` the `BufferedWriter`. In your case this is not only a side note for good practice, but actually the reason for your problem. — bkis, Aug 10 '20 at 13:16

score 0 · Accepted Answer · answered Aug 10 '20 at 14:02

As mentioned in the comments you forgot to close the writer. Instead of out.close() you can also use the new syntax try-with-resources since Java 7:

try (BufferedWriter out = new BufferedWriter(new FileWriter("D:/test.json"))) {
    out.write(data);
}

This will automatically close all Closeables at the end of the try block. Attention: the FileWriter will not be closed by the try-with-resource mechanism as there is no variable created for the FileWriter. Luckily the BufferedWriter.close() will also close the passed FileWriter.

BufferedWriter is not writing data properly

1 Answers1