You use unsafe.putLong(), unsafe.putByte(), unsafe.putInt() to directly store a value into a given memory address. You then use unsafe.getLong() etc to directly read those values back from memory. This get you native C-like performance of only 78 ns, roughly 130 times faster than Java's 11,000 ns, very impressive! But when it comes to allocating memory, you use "new byte[1024]", a straight Java call. Using malloc ie. unsafe.allocateMemory(...), to get a larger byteblock and writing into it would probably speed up the routine even more. You also have the free ie. unsafe.freeMemory for the cleanup. (http://www.docjar.com/docs/api/sun/misc/Unsafe.html )