[sagher]

It looks like licensing issues with java 8 have made it impossible to maintain the repos: https://launchpad.net/~webupd8team/+archive/ubuntu/java

If you have to use it you'll need to get a license and download from oracle: https://www.oracle.com/java/technologies...loads.html

I try it and paste License key also a public key. and all looks ok. after it when try to install oracle java8 or 9 i got same error that 
"E: Package 'oracle-java8-installer' has no installation candidate"