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.
I appreciate your response. The IUSR account is the account that is created by IIS7, and it works as it should. I could do use the application pool setting, though I prefer to have a separate account/account group in use for the websites in case we need to modify the permissions within a specific site.