What is the default encoding of the JVM?

Is UTF-8 the default encoding in Java?
If not, how can I know which encoding is used by default?

The default character set of the JVM is that of the system it's running on. There's no specific value for this and you shouldn't generally depend on the default encoding being any particular value.

It can be accessed at runtime via Charset.defaultCharset(), if that's any use to you, though really you should make a point of always specifying encoding explicitly when you can do so.

Note that you can change the default encoding of the JVM using the confusingly-named property file.encoding.

If your application is particularly sensitive to encodings (perhaps through usage of APIs implying default encodings), then you should explicitly set this on JVM startup to a consistent (known) value.

There are three "default" encodings:

• file.encoding:
  System.getProperty("file.encoding")

• java.nio.Charset:
  Charset.defaultCharset()

• And the encoding of the InputStreamReader:
  InputStreamReader.getEncoding()

You can read more about it on this page.

To get default java settings just use :

java -XshowSettings 

I am sure that this is JVM implemenation specific, but I was able to "influence" my JVM's default file.encoding by executing:

export LC_ALL=en_US.UTF-8

(running java version 1.7.0_80 on Ubuntu 12.04)

Also, if you type "locale" from your unix console, you should see more info there.

All the credit goes to http://www.philvarner.com/2009/10/24/unicode-in-java-default-charset-part-4/

You can use this to print out the JVM defaults

import java.nio.charset.Charset;
import java.io.InputStreamReader;
import java.io.FileInputStream;

public class PrintCharSets {
        public static void main(String[] args) throws Exception {
                System.out.println("file.encoding=" + System.getProperty("file.encoding"));
                System.out.println("Charset.defaultCharset=" + Charset.defaultCharset());
                System.out.println("InputStreamReader.getEncoding=" + new InputStreamReader(new FileInputStream("./PrintCharSets.java")).getEncoding());
        }
}

Compile and Run

javac PrintCharSets.java && java PrintCharSets

It's going to be locale-dependent. Different locale, different default encoding.