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.
Azure Site Recovery, or just ASR, is a Disaster Recovery offering from Microsoft Azure. In a world where IT systems is more critical than ever, the requirements for uptime are getting higher and higher. Most companies do backups of their systems, but backups only get you so far.