To copy a lib file to local one, the MLet reads and writes one byte by one byte, it is possible to read and write once time whole file like:

int i = is.available();
while (i>0) {
int[] b = new int[i];
is.read(b);
fileOutput.write(b);
i = is.available();
}

Another problem is that the MLet may create a directory to save a native lib file, the lib file will be removed when exiting normally, but the directory will not be removed.