Reads the next line of text from the input stream.
It reads successive bytes, converting
each byte separately into a character,
until it encounters a line terminator or
end of
file; the characters read are then
returned as a {@code string}. Note
that because this
method processes bytes,
it does not support input of the full Unicode
character set.
<p>
If end of file is encountered
before even one byte can be read, then {@code null}
is returned. Otherwise, each byte that is
read is converted to type {@code char}
by zero-extension. If the character {@code '\n'}
is encountered, it is discarded and reading
ceases. If the character {@code '\r'}
is encountered, it is discarded and, if
the following byte converts  to the
character {@code '\n'}, then that is
discarded also; reading then ceases. If
end of file is encountered before either
of the characters {@code '\n'} and
{@code '\r'} is encountered, reading
ceases. Once reading has ceased, a {@code string}
is returned that contains all the characters
read and not discarded, taken in order.
Note that every character in this string
will have a value less than {@code \u005Cu0100},
that is, {@code (char)256}.
@return the next line of text from the input stream,
or {@code null} if the end of file is
encountered before a byte can be read.
@exception IOException if an I/O error occurs.
Reads the next line of text from the input stream. It reads successive bytes, converting each byte separately into a character, until it encounters a line terminator or end of file; the characters read are then returned as a {@code string}. Note that because this method processes bytes, it does not support input of the full Unicode character set. <p> If end of file is encountered before even one byte can be read, then {@code null} is returned. Otherwise, each byte that is read is converted to type {@code char} by zero-extension. If the character {@code '\n'} is encountered, it is discarded and reading ceases. If the character {@code '\r'} is encountered, it is discarded and, if the following byte converts  to the character {@code '\n'}, then that is discarded also; reading then ceases. If end of file is encountered before either of the characters {@code '\n'} and {@code '\r'} is encountered, reading ceases. Once reading has ceased, a {@code string} is returned that contains all the characters read and not discarded, taken in order. Note that every character in this string will have a value less than {@code \u005Cu0100}, that is, {@code (char)256}.
@return the next line of text from the input stream, or {@code null} if the end of file is encountered before a byte can be read. @exception IOException if an I/O error occurs.