Exception on download: sun.security.validator.ValidatorException: No trusted certificate found

Question

I\'m trying to use sbt on Ubuntu 16.04, but am getting errors when trying to run it. I did a fresh install, then followed the directions exactly from the sbt site, but get t

Answer 1

On Ubuntu, when you have the package openjdk-9-jre-headless installed, sbt can't verify its downloads because they're not signed against the OpenJDK 9 certificates. To fix this, you need to uninstall OpenJDK 9:

$ apt-get remove openjdk-9-*

Then make sure you have openjdk-8-jre-headless installed, and use update-java-alternatives to select it as the default JRE (see https://askubuntu.com/a/731862/459610 for details).

Answer found at https://medium.com/@henricook/solution-to-sun-security-validator-validatorexception-e300dd7dba70#.wn7uh2z9q

(Note: I'm not on an Ubuntu machine now, so I can't verify this, but: you may be able to get away with just setting the default Java to JDK 8.)