Creating cross platform applications

Question

I have a fair bit of knowledge of Java and C#.NET (prefer C#).

What should I use to create small applications that will work well in Windows, Mac and Linux? Speed will probably not be the main concern (small applications; using Sockets etc).

Answer 1

Java

because

1. Java works on Windows,Linux and Mac and even on Mobile phones.(and its official -@cletus)
2. Java has got good platform independent Sockets Library.
3. Eclipse is great tool for Java Development. (NOTE:you will miss visual studio but not as much)
4. GUI in Java is NOT that BAD.(Example1,Example2)Thanks @Riduidel.
5. I don't think mono is as mature and as good as .NET yet.

Answer 2

Both of those are viable options.

Java is officially supported on all three platforms.

C# can be used on Linux and Mac if you're prepared to use the subset of .Net supported by Mono.

Which is more suitable depends on which you're more comfortable with and the exact requirements of the applications you'll be developing.