Rough Overview of Programming Languages

Java is mainly large enterprise back end systems, and some android, and quite a lot of embedded stuff (nominally what it was invented for), and, worryingly, quite a lot of client side GUI stuff.
C++ is used for legacy systems and where you need speed.

C is used where you need speed, have simple programs and memory constraints, and old fashioned unix software.

C# is for windows programming and .net

Javascript is for browser programming and Node, and some general scripting, where someone has used it as their system’s internal scripting language (see also lua)

PHP is used for relatively simple web stuff, because it’s easy and works and has wide library support

Python is used for what PHP is by better developers, and has brilliant maths libraries so is increasingly used for anything maths related where esoteric things like matlab and R and F# are unhelpfully niche.

Haskell is used for academic curiosity, and some maths stuff.

Perl is dying out, but is still used for unix automation a fair bit.