Java uses the keystore file named cacerts. It should already contain all trusted root CA certificates that are used to sign intermediate and leaf certificates. Leaf certificates are end user certificates that are used to secure websites with HTTPS. However, sometimes a root CA certificate might be missing from the Java keystore or a website might be using a self-signed certificate which will result in the following exception when you try to access the website from Java code: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target For me it happened with a certificate issued by COMODO. In this case the easiest solution is to add the website certificate to the Java keystore. Shortly, it requires exporting the certificate from the website, importing it into the keystore and restarting your Java application. Please b