As far as I know Scala can't have value types (aside from the single member which is useless from performance perspective) for eg. you cannot do things like "std::vector<point3f>" and have that allocate a flat array of size N * size of 3 floats, instead it will allocate a array of pointers to point3f type objects and then do allocation for point3f N times and will also allocate extra memory for each point3f object for bookkeeping which is really significant when you're dealing with such small objects in large numbers.
This is courtesy of JVM not having value types, and that's just one obvious performance dead end if you write code that deals with that sort of thing (both in memory usage and in access time/runtime). There's plenty of other stuff that makes JVM not suitable for performance sensitive work, as long as we aren't defining performance sensitive as "faster than Python and Ruby".
Web apps seem to be IO bound so runtime performance generally doesn't matter.
This is courtesy of JVM not having value types, and that's just one obvious performance dead end if you write code that deals with that sort of thing (both in memory usage and in access time/runtime). There's plenty of other stuff that makes JVM not suitable for performance sensitive work, as long as we aren't defining performance sensitive as "faster than Python and Ruby".
Web apps seem to be IO bound so runtime performance generally doesn't matter.