illegal unicode escape

[Brajmohan Jangir]

public class Hello{
//Commented character '\uFF'
}

Compiler shows me "illegal unicode escape".
Please can you explain me why compiler looks inside commented code?

I am working on Windows and using jdk 1.6.

Thanks in Advance.

[Pondurai Singh]

You could work around it by inserting a space char after the backslash

[Brajmohan Jangir]

Thanks a lot for quick response.
I really appreciate your answer.

But I am looking for the cause of this compilation failure.
Why this comment fails the compilation?

[Pondurai Singh]

Unicode Escapes

A compiler for the Java programming language ("Java compiler") first recognizes Unicode escapes in its input, translating the ASCII characters \u followed by four hexadecimal digits to the UTF-16 code of the indicated hexadecimal value, and passing all other characters unchanged. Representing supplementary characters requires two consecutive Unicode escapes. This translation step results in a sequence of Unicode input characters.

UnicodeInputCharacter: 
    UnicodeEscape
    RawInputCharacter

UnicodeEscape:
    \ UnicodeMarker HexDigit HexDigit HexDigit HexDigit

UnicodeMarker:
    u
    UnicodeMarker u

RawInputCharacter:
    any Unicode character

HexDigit: one of
    0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F

In addition to the processing implied by the grammar, for each raw input character that is a backslash \, input processing must consider how many other \ characters contiguously precede it, separating it from a non-\ character or the start of the input stream. If this number is even, then the \ is eligible to begin a Unicode escape; if the number is odd, then the \ is not eligible to begin a Unicode escape.

[Brajmohan Jangir]

I got the reason.
It means compiler tries to translate the ASCII characters \u followed by hexadecimal digits to UTF-16 code and if compiler founds any illegal Unicode escape then it fails.

Thank you very much...