Java UTF-8 String does not match C# UTF-8 String

Question

I have two byte array from( in C# and Java ) a string. When I convert arrays, the results do not match. What could be the reason for this? This problem is not constant. Sometimes it produces the same results.

C# result : �F&��j9�\r��

Java Result : �F&��j9�0��

Edit :

Converter Code;

C# -
String result = UTF8Encoding.UTF8.GetString(byteArray);

Java: 
String result = new String(byteArray, "UTF-8");

*Edit-2 : Its true convert.

C# :
        [0] 239 
        [1] 195 
        [2] 40  
        [3] 19  
        [4] 185 
        [5] 36  
        [6] 77  
        [7] 132 
        [8] 182 
        [9] 122 
        [11]    173 
        [12]    12  
        [13]    191 
        [14]    100 
        [15]    118 
Java :

0 = -17
1 = -61
2 = 40
3 = 19
4 = -71
5 = 36
6 = 77
7 = -124
8 = -74
9 = 122
10 = -70
11 = -83
12 = 12
13 = -65
14 = 100
15 = 118

C# result : ��(�$M��z��dv Java result : ��(�$M��z��dv*

Those are the same values, it just seem that you display them in a different format. They are unsigned in C# (range 0 / 255) and signed in Java (range -128 / +127) — Kevin Gosse
– Kevin Gosse, Commented Jul 11, 2017 at 6:34
Please provide a minimal reproducible example which shows the UTF-16 code units of the resulting strings. Also indicate where the bytes came from. If they weren't UTF-8-encoded text to start with, you shouldn't be trying to decode them as UTF-8. — Jon Skeet
– Jon Skeet, Commented Jul 11, 2017 at 7:02
@JonSkeet java : value.getBytes(Charset.forName("UTF-8")); C# : UTF8Encoding encoder = new UTF8Encoding(); encoder.GetBytes(value); .. and I can not change C# code. Its in server — fatih bolat
– fatih bolat, Commented Jul 11, 2017 at 7:06
So you should know what the original string is, and you should be able to say which decoding is going wrong. Please provide a minimal reproducible example, which will make it much easier to help you. — Jon Skeet
– Jon Skeet, Commented Jul 11, 2017 at 7:15

Eran · Accepted Answer · 2017-07-11 06:40:33Z

3

I'm assuming the outputs you displayed above are the byte arrays corresponding with the String in C# and Java.

byte in Java is a signed type (between -128 and 127), which explains the negative values for some of the bytes.

It looks like all the values that are positive for Java match the corresponding C# values, and only the negative values in Java don't match the corresponding C# values. The reason for that is that C# bytes are unsigned (between 0 and 255).

If you print the unsigned values corresponding with the Java bytes, you should get the same output as in C#:

for (byte b : byteArray)
    System.out.println(b & 0xff);

edited Jul 11, 2017 at 6:40

answered Jul 11, 2017 at 6:34

Eran

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6 Comments

fatih bolat Over a year ago

OK, but for some arrays (Java: signed, C #: unsigned) it can produce the same results in both.

Eran Over a year ago

@fatihbolat Of course, if all the bytes happen to be between 0 and 127, both Java and C# would produce the same output.

fatih bolat Over a year ago

stackoverflow.com/a/45027202/8287517 @eran. @H B is right. So I expect to produce the same strings. However, this is not the case in some cases.

Eran Over a year ago

@fatihbolat How did you produce these byte arrays?

fatih bolat Over a year ago

java : value.getBytes(Charset.forName("UTF-8")); C# : UTF8Encoding encoder = new UTF8Encoding(); encoder.GetBytes(value); @Eran

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Sunil Kanzar · Accepted Answer · 2017-07-11 06:52:32Z

1

Binary value for -108 and 148 both are same.

In java if you convert string to byte array then value of char grater then 127 is converted to negative value.

Look at value of 148 the windows calculator :

And same value for -108 :

Now discard the bits after first 8 bit and that is 1001 0100 which is same in both. Note : Need to discard, because length of byte is 8 bit.

edited Jul 11, 2017 at 6:52

answered Jul 11, 2017 at 6:44

Sunil Kanzar

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