What encoding/character set does Java use per default for BufferedReader?

Question

What encoding/character set does Java use per default when we create a new BufferedReader object without providing an encoding explicitly?

For example:

try (final BufferedReader reader = new BufferedReader(new FileReader("my_file.txt"))) {
  reader.readLine(); // What encoding is used to read the file?
}

If you want to know how the default is set, dupe stackoverflow.com/questions/361975/… stackoverflow.com/questions/1006276/… stackoverflow.com/questions/1749064/… stackoverflow.com/questions/2677419/… and more — dave_thompson_085
– dave_thompson_085, Commented Sep 1, 2018 at 15:41

Stephen C · Accepted Answer · 2018-09-11 09:22:34Z

5

BufferedReader doesn't do any decoding. It is a wrapper for another Reader ... which may or may not do decoding.

FileReader decodes using the JVM's default character encoding, as returned by Charset.defaultCharset()

The javadoc states:

Convenience class for reading character files. The constructors of this class assume that the default character encoding and the default byte-buffer size are appropriate. To specify these values yourself, construct an InputStreamReader on a FileInputStream.

edited Sep 11, 2018 at 9:22

answered Sep 1, 2018 at 8:16

Stephen C

723k95 gold badges849 silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

xingbin · Accepted Answer · 2018-09-01 08:26:29Z

4

FileReader is an InputStreamReader which uses FileInputStream as input, and an InputStreamReader uses the default charset when constructed without specified charset.

In the source code jdk10, it use Charset.defaultCharset():

public static StreamDecoder forInputStreamReader(InputStream in,
                                                 Object lock,
                                                 String charsetName)
    throws UnsupportedEncodingException
{
    String csn = charsetName;
    if (csn == null)
        csn = Charset.defaultCharset().name(); // get default charset
    try {
        if (Charset.isSupported(csn))
            return new StreamDecoder(in, lock, Charset.forName(csn));
    } catch (IllegalCharsetNameException x) { }
    throw new UnsupportedEncodingException (csn);
}

which

Returns the default charset of this Java virtual machine.

The default charset is determined during virtual-machine startup and typically depends upon the locale and charset of the underlying operating system.

You can print it:

public static void main(String[] args) {
    System.out.println(Charset.defaultCharset());
}

edited Sep 1, 2018 at 8:26

answered Sep 1, 2018 at 8:13

xingbin

28.4k12 gold badges62 silver badges111 bronze badges

1 Comment

Tim Biegeleisen Over a year ago

You should include an actual JavaDoc reference which connects this to FileReader; I could not find one.

Collectives™ on Stack Overflow

What encoding/character set does Java use per default for BufferedReader?

2 Answers 2

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related