Java is a programming language and computing platform first released by Sun Microsystems in 1995. There are lots of applications and websites that will not work unless you have Java installed, and more are created every day.
IIS is able to impersonate the IUSR_<computername> account because the user name and password for this account are known by IIS. Before returning a page to the client, IIS checks NTFS file and directory permissions to see if the IUSR_<computername> account is allowed access to the file.
Repeat step 5 to add any additional service accounts to the to the IIS_IUSRS group. For the business management server, you add the CatalogWebSvc, MarketingWebSvc, OrdersWebSvc, and ProfilesWebSvc accounts to the IIS_IUSRS group. In the IIS_IUSRS Properties dialog box, click OK.