Check the encoding (default) of the current Java implementation on the system.

CheckEncoding.java

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.nio.charset.Charset;

public class CheckEncoding {

    public static void main(String[] args) {
        System.out.println("Default Charset = " + getDefaultCharset());
        System.out.println("System Property (file.encoding) = " + getFileEncoding());
        System.out.println("Default Charset in Writer = " + getWriterEncoding());
        System.out.println("Default Charset in Reader = "  + getReaderEncoding());
    }

    public static String getWriterEncoding() {
        OutputStreamWriter writer = new OutputStreamWriter(new ByteArrayOutputStream());
        String encoding = writer.getEncoding();
        return encoding;
    }
    
    public static String getReaderEncoding() {
        byte[] buffer = new byte[8];
        InputStreamReader reader = new InputStreamReader(new ByteArrayInputStream(buffer));
        String encoding = reader.getEncoding();
        return encoding;
    }
    
    public static String getDefaultCharset() {
        return Charset.defaultCharset().name();
    }
    
    public static String getFileEncoding() {
        return System.getProperty("file.encoding");
    }
}