Конвертирование строки в байты через getBytes(encoding), странные результаты

public static void main(String[] args) throws UnsupportedEncodingException {
    String s0="H\u00ebllo";
    String s1="Hëllo";
 
    byte[] bytes=s0.getBytes("ISO8859_1"); //72 -21 108 108 111
    //byte[] bytes=s1.getBytes("ISO8859_1"); //72 -61 -85 108 108 111
    //byte[] bytes=s0.getBytes("UTF-8");  //72 -61 -85 108 108 111
    //byte[] bytes=s1.getBytes("UTF-8");  //72 -61 -125 -62 -85 108 108 111
    for (int i=0,  i<bytes.length; i++)  {
        System.out.println(bytes[i]);
    }
}

ë(ISO8859_1) = 0xeb = 235 = 11101011 = -21 (two's complement for signed numbers)
 
ë (UTF-8) = 0xc3 0xab => 0xc3 = 195 = 11000011 = -61, 0xab = 171 = 10101011 = -85

import java.nio.charset.StandardCharsets;
import java.util.Objects;
 
public final class Utf8 {
 
    public static void main(final String[] args) {
        final String s = "HГ«llo";
        final byte[] sBytes = s.getBytes(StandardCharsets.UTF_8);
        System.out.println(toBinaryString(sBytes, " "));
    }
    
    private static String toBinaryString(final byte[] bytes, final String separator) {
        Objects.requireNonNull(bytes);
        Objects.requireNonNull(separator);
        if (bytes.length == 0) {
            return "";
        }
        final StringBuilder sb = new StringBuilder((8 + separator.length()) * bytes.length);
        sb.append(toBinaryString(bytes[0]));
        for (int i = 1; i < bytes.length; i++) {
            sb.append(separator).append(toBinaryString(bytes[i]));
        }
        return sb.toString();
    }
    
    private static String toBinaryString(final byte b) {
        return String.format("%8s", Integer.toBinaryString(b & 0xFF)).replace(' ', '0');
    }
}