What is the new JDBC 4.3 Connection Request feature with `beginRequest` & `endRequest` methods?
These new JDBC4.3 APIs beginRequest and endRequest have to do with connection management. It's really a hint provided by the connection pool to the driver that a connection has been checked out of the pool (beginRequest) or checked back into the pool (endRequest). Without these APIs the driver has really no clue about request boundaries. The driver can then use these request demarcations to do dirty laundry like pinging the database, replacing the connection without another one for load balancing, clearing out dirty states, etc.

These APIs were defined as Oracle specific APIs in the Oracle JDBC thin driver before JDBC4.3. Oracle's UCP (Universal Connection Pool) already calls these APIs. Now that they are part of the standard, other connection pools can start using them (and other drivers will implement them).