Dieharder input data format. Do I need new line at the end?
Looking at the source, file_input_get in dieharder-3.31.1/libdieharder/rng_file_input.c: you are safe with a single newline after the last decimal number, as supplied by Java's writer.println. You do not need an extra newline. If there was a problem, DieHarder would stop with "# file_input(): Error: EOF on (filename)" or "Error: converting (stuff) failed. Exiting."

But this is kinda off-topic.