jodd-core/src/main/java/jodd/io/FileNameUtil.java
public static int indexOfLastSeparator(final String filename) {
		if (filename == null) {
			return -1;
		}
		int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
		int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
		return Math.max(lastUnixPos, lastWindowsPos);
	}
public static int indexOfLastSeparator(final String filename) {
		if (filename == null) {
			return -1;
		}
		int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
		int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
		return Math.max(lastUnixPos, lastWindowsPos);
	}
Returns the index of the last directory separator character.
<p>
This method will handle a file in either Unix or Windows format.
The position of the last forward or backslash is returned.
<p>
The output will be the same irrespective of the machine that the code is running on.

@param filename  the filename to find the last path separator in, null returns -1
@return the index of the last separator character, or -1 if there is no such character