HttpServletRequest.getRequestURL returns empty - Behind F5 Load Balancer & Apache Reverse Proxy Server

We have the below configuration.

F5 Load Balancer -> Apache Reverse Proxy Server -> Application Server

We see that HttpServletRequest.getRequestURL() is returning NULL in this configuration.

If we directly access Apache Reverse Proxy URL, this works!

Is there some configuration in F5 to pass URL correctly or is there some configuration in Apache to ensure that it receives the URL from F5?