What version of Java did you use? What about experience with Postgres — just queries or optimization too?

I have used Java starting from version 8 and above, including Stream API features, lambda expressions, and modularity (Java 9+). Regarding PostgreSQL, I have experience not only in writing complex SQL queries but also in optimization: creating indexes, analyzing execution plans (EXPLAIN), tuning database parameters for performance, as well as working with materialized views and table partitioning for scalability.