How to resolve java.net.UnknownHostException when connecting to localhost by hostname
Many a times while working with Java applications, in my case scala (spark), which use your hostname (not localhost) but the actual name you gave to your system, like I use rohit.tuplejump.com , will fail to connect throwing an UnknownHostException. If you do a hostname -f, it will say "Name or service not known" Many people use the solution of adding the this entry to /etc/hosts but that needs to be changed every time your public IP changes. The better solution is to use the nss-myhostname package. The package is generally installed on any linux distribution, in case it isn't you can search and install it using your package manager. On Fedora you can do, $ sudo yum install nss-myhostname Then edit your /etc/nsswitch.conf to add myhostname in the line which begins with "hosts:". This will tell the system to use bind your system hostname to your public IP address. On my system this line looked like, hosts: files mdns4...