Question

Is anyone attempting to implement C# for the JVM? As a Java developer, I’ve been eyeing C# with envy, but am unwilling to give up the portability and maturity of the JVM, not to mention the diverse range of tools for it.

I know there are some important differences between the JVM and CLR but is there anything that is a showstopper?

Answer 1

There are very significant differences between the CLR and the JVM.

A few examples:

• Java doesn’t have user-defined value types
• Java generics is completely different to .NET generics
• Many aspects of C# depend on elements of the framework – delegates etc. You’d need to port the library as well, even for language aspects.
• Java doesn’t support things like properties and events at a JVM level. You could fake some of this, but it wouldn’t be the same.
• I don’t believe Java has any equivalent to pass-by-reference parameters, even at the JVM level
• Subtleties to do with the different memory models would quite possibly bite, although I’m not sure how much is in the C# spec.
• Unsafe code in general probably isn’t possible in Java
• Interoperability with native code is very different between JNI and P/Invoke. This probably isn’t much of a problem for you.
• You’d have to fake operator overloading and user-defined conversions

You could probably port a lot of C# – but you’d be left with a pretty unsatisfactory experience, IMO.

Going the other way, are you aware of IKVM? It allows you to run Java code in .NET.