There are four different types of warehousing: private, public, contract, and cross-docking. Private warehousing is when a company uses their own warehouse to store their products. This is usually only done by larger companies who have the resources to build and maintain their own warehouse. Public warehousing is when a company rents space from a warehouse that is already built and maintained by someone else. Contract warehousing is when a company outsources the management of their warehouse to another company. This option is often used by companies who do not have the time or resources to manage their own warehouse and logistics. Cross-docking is when products are unloaded from one truck and loaded onto another truck without being stored in a warehouse.