I have Postgres RDS database in AWS configured with the rds-ca-rsa2048-g1 certificate.

In my Java application I use the following connection URL:

jdbc:postgresql://my-db-name.ajsa891hjkdas.eu-central-1.rds.amazonaws.com:5432/mydb?searchpath=dataset?ssl=true&sslmode=require

At the application startup I set the JVM properties:

-Djavax.net.ssl.trustStore=app/truststore.jks
-Djavax.net.ssl.trustStorePassword=mypass

In the truststore I have currently only Amazon Root CA, but no rds-ca-rsa2048-g1 imported.
However, the connection seems to be working. Why is it so? What should I do in order to properly configure the SSL connection?

Thank you in advance!

I expect working SSL connection between my Java application and RDS.