The process of converting unicode escape sequences to characters happens
somewhere between reading the source file, and then parsing source file for
compilation.

   So javac will read in the file, and thus get:

////////////////////
// char c = '\u000a'
////////////////////

   Then it will convert unicode escape sequences to their equivalent
characters and get:

////////////////////
// char c = '
'
////////////////////

   And then it will try to compile this code, and it'll fail with some sort
of error like "Not expecting apostrophe here".

   - Oliver

Yes.

Read section 3.2 of the JLS, which describes translation of the input
to the compiler. The unicode escape sequences are translated into
their corresponding unicode characters, *then* the resulting sequence
of characters is tokenized.

So when you escape a line feed as you've done, you are essentially
writing this (illegal) code:

 char c = '
 '

i.e. the closing quote ends up on the following line.

Similarly, commenting the line results in this invalid sequence:

 // char c = '
 '

/gordon

Yes, exactly right.

   -- chris