The plprofiler project provides great tooling to address questions such as which line inside a function or block of code is causing the slowness in function calls.
With C++17 we get another facility to handle the conversion between text and numbers. Why should we care about the new routines? Are they better in any way?
Has JavaScript become better for server-side development than Java? It might just depend on the app under development. I can hear the moans from the Java devs now...
Unless you are in the development stone age and SSHing into the production servers to hand edit files with Vim or Emacs, your development environment is not the same as production.