Charset.defaultCharset() and file.encoding is JVM's charset, not charset of OS, console and terminal.
Now I create a Process to run a program, and use process.getInputSteam() to read the output, how to find the correct charset for the process (sun.jnu.encoding is right but it seems not general)?
From Java 17 onwards, there is a method in Process class named inputStream.
The source code taken from Process.java:
public final BufferedReader inputReader() {
return inputReader(CharsetHolder.nativeCharset());
}
The nativeCharset is obtained from System property "native.encoding".
This property was introduced in Java 17. This is probably what you want.