Currently java-driver ignores the peers that have null rpc_address. We see many cases in production where rpc_address is not null but many other key fields are left null by cassandra for invalid peers. Driver establishing connections to these nodes is a bad idea.
Tighten the peer validity check. isValidPeer() need to include the null check for the following fields:
Ignore all the peers that are invalid as per above check.
I have attached an example that shows many invalid peers.