Maven - Debugging the PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

From time to time that infamous exception attacks us. Usually, it is just as simple as import the valid key to your cacerts trustStore or specify the right path. But what if that does not help this time? After double check everything seems to be right. It's time to dive deeper. 

That simple debug steps make your live longer:

 

1. check the actual settings were applied: `-XshowSettings:properties` 
2. If still no idea what's wrong, try the ultimate weapon: `--Djavax.net.debug=all` - and be prepared for long log file ;). 

And couple more takeaways: 

1. The `.mavenrc` overrides whatever comes even in MAVEN_OPTS passed from environment.
2. The `${USER}` variable is not evaluated when put into `${PRJECT_DIR}/.mvn/jvm.config` file.