jodd-core/src/main/java/jodd/util/Format.java
public static String humanReadableByteCount(final long bytes, final boolean useSi) {
		final int unit = useSi ? 1000 : 1024;
		if (bytes < unit) return bytes + " B";
		final int exp = (int) (Math.log(bytes) / Math.log(unit));
		final String pre = (useSi ? "kMGTPE" : "KMGTPE").charAt(exp-1) + (useSi ? "" : "i");
		return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
	}
public static String humanReadableByteCount(final long bytes, final boolean useSi) {
		final int unit = useSi ? 1000 : 1024;
		if (bytes < unit) return bytes + " B";
		final int exp = (int) (Math.log(bytes) / Math.log(unit));
		final String pre = (useSi ? "kMGTPE" : "KMGTPE").charAt(exp-1) + (useSi ? "" : "i");
		return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
	}
Formats byte size to human readable bytecount.
https://stackoverflow.com/questions/3758606/how-to-convert-byte-size-into-human-readable-format-in-java/3758880#3758880