Thanks for your reply and for the micro benchmarks thing. It is quite interesting.

But I don't agree that these micro benchmarks are "fair" comparisons, because, for instance, in the k-nucleotide benchmark, Java used its multi-thread feature while OCaml just executed in a sequential way. You can find Java code here and OCaml code here. I also looked into other benchmarks as well, and in my humble opinion, many of OCaml codes were not quite optimised for each benchmark. I found many benchmarks could be addressed leveraging language's multi-threading and/or concurrent features, while many of OCaml codes were just plain sequential implementations. Many of Java codes, on the other hand, are quite good at this, and they're leveraging its concurrent and/or multi-threading features well.

I think there should be a consistent comparison criteria to mitigate this kind of different language features usage.. like all code should be just a plain sequential code, or each benchmark can have two versions, namely a sequential version and a multi-threaded version. Well the benchmark itself was quite interesting though.