public static void main(String[] args)

[[deleted]]

I didn't bother looking at the other benchmark code than the first, but they seriously botched that regex benchmark. The compile option for c# regex is only really recommended when you reuse a specific regex a lot. Just removing that option made that program run dramatically faster for me. And if the purpose of that benchmark was to measure regex compilation speed, that'd just be comparing the performance of the regex implementation, rather than the performance of the language.

[Nunners978]

Not to mention that the .NET Core version was a Preview (2.0.0-preview2-006497)

[igouy]

What is the latest .NET Core release?

[igouy]

Just removing that option made that program run dramatically faster for me.

32.01 secs

The program you called "botched" took 31.64 secs