Java: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Question

I have a class that will download a file from a https server. When I run it, it returns a lot of errors. It seems that I have a problem with my certificate

Answer 1

Here's what reliably works for me on macOS. Make sure to replace example.com and 443 with the actual hostname and port you're trying to connect to, and give a custom alias. The first command downloads the provided certificate from the remote server and saves it locally in x509 format. The second command loads the saved certificate into Java's SSL trust store.

openssl x509 -in <(openssl s_client -connect example.com:443 -prexit 2>/dev/null) -out ~/example.crt
sudo keytool -importcert -file ~/example.crt -alias example -keystore $(/usr/libexec/java_home)/jre/lib/security/cacerts -storepass changeit