utf-8 encoding

[HaYa aziz]

Dear All..
In building a Nutch plug-in, I used to declare a string of Arabic word
while compiling using ant, I'm getting this error :

"unmappable character for encoding UTF-8"

trying the following but with no luck :

String s = new String ("النوع");//the Arabic word
          byte[] utf8Bytes = s.getBytes("UTF8");
          byte[] defaultBytes = s.getBytes();
          s = new String(utf8Bytes, "UTF8");

the exception appear in every singe Arabic character

any help?

Thanks