[Silhouette]

I think I half-agree with you. I don't think a great library can ever elevate an OK language to great. However, a poor library can certainly drag an OK language down to poor.

One of the most complicated decisions in developing any new programming language today must surely be where to draw the line separating standard library facilities from those to be provided externally. Provide too little, and you get a zillion incompatible external implementations popping up (C++ and strings; JavaScript and DOM manipulations). On the other hand, go too far, and you get your entire community relying on mediocre facilities, or worse, multiple competing facilities in your own standard (Java and GUIs; D in general). Likewise, if you have a common repository for additional libraries, you can be too restrictive on contributions and wind up with many basics still not covered (C++ and Boost) or you can be too open and wind up with a whole load of substandard or incomplete junk (Perl and CPAN).

[Markku]

Yes, Java is not elevated to great language status by the wealth of libraries. It gets the job done and it is possible to be productive with it, but many times you have to fight it. The language drags the libraries down in this case. In most other modern languages, I would say the libraries are what matters.

Racket has a decent repository (PLaneT) for libraries and easy ways to wrap C libraries.

[Silhouette]

Exactly. Looking from the other side, I suspect Java's much more comprehensive library caused more programmers to favour it over C++ than Java's garbage collection ever did.

I think the almost symbiotic relationship between C# and the .Net libraries today is an interesting case. It seems clear that several of the language features added to C# (or the underlying .Net execution model, if you prefer) in recent years were motivated by particular ways of working with the libraries. Usually, we see mostly one-way traffic, with standard libraries trying to paper over any cracks in the underlying language.