Using the PostgreSQL JDBC driver since 42.2.5, the SSL behaviour changed which can cause FileNotFoundExceptions looking for .postgresql/root.crt.

As a workaround you can add sslmode=require (no certificate validation!) or sslfactory=org.postgresql.ssl.DefaultJavaSSLFactory (validate certificate using JRE trust store) to your JDBC URL.

Therefore a working JDBC URL looks like this:

This behavior and the mentioned workaround are described in