Is it? Java has changed a lot, but in such a way that it's still easy to mentally map new features to the old ones, provided you have understood the core language. IDEs can even convert your code from old to new and back.
Still true for C++. Can still mentally map new features to the core language C. A modern Cfront transpiler can still be written.
Template meta-programming maps to C pre-processor macros. The sad part with both is generated code cannot be examined thus the unreadable compiler errors and slower compilation as it's regenerated every time.
Slightly off-topic: Rust can also be mentally mapped to C.
Yeah it is! Java 25 changed constructor behaviour to allow logic to run before the calls to super(). That’s an enormous change.
On the c++ side, “modern” features like span, smart pointers, range based for loops, format are all really simple to reason back to for anyone who is a programmer. Stuff like modules and concepts is a bit different, but most people aren’t in the innards of those every day, in the same way that the change in header size doesn’t affect every single Java developers code, but you should know about it.
Is it? Java has changed a lot, but in such a way that it's still easy to mentally map new features to the old ones, provided you have understood the core language. IDEs can even convert your code from old to new and back.