尝试包含Urdu字符串时为什么会出现编译错误？

Question

I am trying to add an urdu string غزل as shown below:

class UnicodeCheck {
  public static void main(String args[]) {
   try {
    File f = new File("C:/Users/user/Desktop/unicodecheck.txt");
    FileWriter writer = new FileWriter(f);
    writer.write("غزل");
    writer.close();
   } catch(Exception exc) {
       exc.printStackTrace();
     }
 }
}

When I try to compile the above program I get this error.

UnicodeCheck.java:1: illegal character: \187
class UnicodeCheck {
 ^
UnicodeCheck.java:1: illegal character: \191
class UnicodeCheck {
  ^
2 errors

I do not understand this error. Why do I get this and how can I get over this error?

Answer 1

Byte order mark

The byte order mark (BOM) is a Unicode character used to signal the endianness
(byte order) of a text file or stream. Its code point is U+FEFF. BOM use is
optional, and, if used, should appear at the start of the text stream. 
Beyond its specific use as a byte-order indicator, the BOM character may also 
indicate which of the several Unicode representations the text is encoded in.

So You need to strip the BOM or convert your source file to another encoding. Notepad++ can convert a single files encoding, I'm not aware of a batch utility on the Windows platform for this.

Answer 2

The characters in the beginning of the file come from the the Byte Order Mark that some text editors like to insert into the beginning of a file. The Java compiler however does not accept files with BOM. You have two options:

1. Use a text editor that allows saving files in Unicode without BOM, such as Notepad++.

2. Use only ASCII characters in source code. Where you need Unicode characters use \\uXXXX -escape codes. The JDK comes with a utility program to convert "native" text into this encoding, called native2ascii . For example,

    writer.write("غزل"); 

   would be converted into

    writer.write("\غ\ز\ل"); 

Answer 3

It depends on the charset used by your Text editor (where you edit the java source file). Try to set it in UTF-8 format.