Differences between MSIL and Java bytecode?
.net, bytecode, cil, java
Solution
First off let me say that I don't think that the subtle differences between Java bytecode and MSIL is something that should bother a novice .NET developer. They both serve the same purpose of defining an abstract target machine which is a layer above the physical machine being used in the end.
MSIL and Java bytecode are very similar, in fact there is was a tool called Grasshopper which translates MSIL to Java bytecode, I was part of the development team for Grasshopper so I can share a bit of my (faded) knowledge. Please note that I stopped working on this around when .NET framework 2.0 came out so some of these things may not be true any more (if so please leave a comment and I'll correct it).
- .NET allows user defined types that have value semantics as apposed to the regular reference semantics (`struct`).
- .NET supports unsigned types, this makes the instruction set a bit richer.
- Java includes the exception specification of methods in the bytecode. Although exception specification is usually only enforced by the compiler, it may be enforced by the JVM if a class loader other than the default one is used.
- .NET generics are expressed in IL while Java generics only use type erasure.
- .NET attributes have no equivalent in Java (is this still true?).
- .NET `enums` are not much more than wrappers around integer types while Java `enums` are pretty much fully fledged classes (thanks to Internet Friend for commenting).
- .NET has `out` and `ref` parameters.
There are other language differences but most of them are not expressed at the byte code level, for example, if memory serves, Java's non-`static` inner classes (which do not exist in .NET) are not a bytecode feature, the compiler generates an additional argument to the inner class's constructor and passes the outer object. The same is true for .NET lambda expressions.
Problem
I'm new to .Net and I'm trying to understand the basics first. What is the difference between MSIL and Java bytecode?