No need to get rude, yes, I read your link. The discussion on floating ip address is a function of the load balancer.
From your diagram LOAD BALANCER failover in the flow diagram.
The SRX does not do loadbalancing. It can do destination nat to forward an address to a single downstream ip address as the links above note. What it cannot do is have two servers conencted to that same ip and port as shown in your sample diagram.
For high availablity on this function the SRX can be put into a chassis cluster so that a second firewall will take over for the failed firewall.
https://kb.juniper.net/InfoCenter/index?page=content&id=KB15650