write a function that determines whether a computer is big endian or little endian in java

Question

I've reed this code which is in C format but i didn't understand what's the process exactly. can anyone explain it for me in java or if there is a better way in java could you please write it here? thank you

bool endianess(){
 int testNum;
 char *ptr;

 testNum=1;
 ptr=(char*) &testNum;
 return (*ptr); //* return the byte at the lowest address
}

That's a difficult question. The JVM is always big endian, so you'll need to invoke native code to determine the host machine endianess (if that's what you're asking). — Elliott Frisch, Jan 30 '14 at 04:03
Short answer: You can't, other than by querying system attributes or doing strange things with memory-mapped buffers. — Hot Licks, Jan 30 '14 at 04:08

score 4 · Accepted Answer · edited May 23 '17 at 12:08

In a Little Endian architecture, the integer value 0x1 will be written out in memory like

0x1 0x0 0x0 ....

so that function will return 1

Conversely, in a Big Endian architecture, the order of bytes will be

0x0 0x0 ... 0x1

however many bytes are in an int (greater or equal to 2 for it to work), and so

this function will return 0.

Here's a reference for why it can't be done in Java directly, but you could use JNI to escape out to a C library and return the result.

score 1 · Answer 2 · answered Jan 30 '14 at 04:18

1

You may use System.getProperty("sun.cpu.endian"). Alternately, you may use SIGAR (https://github.com/hyperic/sigar), Java native access, JNI etc. to get this information.

answered Jan 30 '14 at 04:18

Nipun Talukdar

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write a function that determines whether a computer is big endian or little endian in java

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