In adjustColumnWidths(), we set the member variable lineFormat, which is used by ProcessPath() to print directory entries. Owners and groups are formatted using the formatting conversion %-Xs, where X is the max length of the owner or group. However, when trying this with an S3 URL, I found that the owner and group were empty (""). This caused X to be 0, which means that the formatting conversion is set to %-0s. This caused a MissingFormatWidthException to be thrown when the formatting string was used in ProcessPath().
Formatting conversions are described here:
The specific exception thrown (a subtype of IllegalFormatException) is described here: