Anything you ZIP/ARJ/RAR/BZIP/GZIP up is inherentely lossless. These formats are designed to store an exact copy of information (like documents, executable files, etc.) where you cannot afford to lose a single byte.
Any of these general purpose 'archivers' use lossless compression.
Certain types of files use lossy compression (like JPG, MP3, OGG) -- those will sacrifice part of the information available in order to save diskspace, but those compressions methods are part of the actual file format itself, not a container holding the media.
Any of these general purpose 'archivers' use lossless compression.
Certain types of files use lossy compression (like JPG, MP3, OGG) -- those will sacrifice part of the information available in order to save diskspace, but those compressions methods are part of the actual file format itself, not a container holding the media.