The source file. Returns null if no file information is
available.
line
int line()
The line in the source file. The first line is numbered 1;
0 means no line number information is available.
column
int column()
The column in the source file. The first column is
numbered 1; 0 means no column information is available.
Columns count characters in the input stream; a tab
advances the column number to the next 8-column tab stop.