You need to exchange binary data between C and Java.
Use the network byte-ordering macros.
The program that created the file
read by the program in the previous recipe was not written in Java,
but in C. Since the earliest days of the TCP/IP protocol in the
1980s, and particularly on the 4.2 BSD version of Unix, there was an
awareness that not all brands of computers store the bytes within a
word in the same order, and there was a means for dealing with it.
For this early heterogeneous network to function at all, it was
necessary that a 32-bit word be interpreted correctly as a
computer’s network address, regardless of whether it originated
on a PDP-11, a VAX, a Sun workstation, or any other kind of machine
then prevalent (there were no “IBM PC” machines powerful
enough to run TCP/IP at that time). So network byte
order was established, a standard for which bytes go in
which order on the network. And the network byte order macros were
for network-to-host order for a
long (32 bits),
host-to-network order for a short (16 bits), and so on. In most Unix
implementations, these C macros live in one of the
Internet header files, although
in some newer systems they have been segregated out into a file like
<machine/endian.h>, as on our OpenBSD
The designers of Java, working at Sun, were well aware of these issues, and chose to use network byte order in the Java Virtual Machine. Thus a ...