call instance void Car::Move(int32) Metadata The Common Language Infrastructure (CLI) records information about compiled classes as metadata. Like the type library in the Component Object Model, this enables applications to support and discover the interfaces, classes, types, methods, and fields in the assembly. The process of reading such metadata is called "reflection". Metadata can be data in the form of "attributes". Attributes can be customized by extending the Attribute class. This is a powerful feature. It allows the creator of the class the ability to adorn it with extra information that consumers of the class can use in various meaningful ways, depending on the application domain. Example Below is a basic Hello, World program written in CIL assembler. It will display the string "Hello, world!". .assembly Hello {} .assembly extern mscorlib {} .method static void Main() { .entrypoint .maxstack 1 ldstr "Hello, world!" call void [mscorlib]System.Console::WriteLine(string) ret } The following code is more complex in number of opcodes. This code can also be compared with the corresponding code in the article about Java bytecode. static void Main(string[] args) { for (int i = 2; i < 1000; i++) { for (int j = 2; j < i; j++) { if (i % j == 0) goto outer; } Console.WriteLine(i); outer:; } } In CIL assembler syntax it looks like this: .method private hidebysig static void Main(string[] args) cil managed { .entrypoint .maxstack 2 .locals init (int32 V_0, int32 V_1) ldc.i4.2 stloc.0 br.s IL_001f IL_0004: ldc.i4.2 stloc.1 br.s IL_0011 IL_0008: ldloc.0 ldloc.1 rem brfalse.s IL_001b ldloc.1 ldc.i4.1 add stloc.1 IL_0011: ldloc.1 ldloc.0 blt.s IL_0008 ldloc.0 call void [mscorlib]System.Console::WriteLine(int32) IL_001b: ldloc.0 ldc.i4.1 add stloc.0 IL_001f: ldloc.0 ldc.i4 0x3e8 blt.s IL_0004 ret } This is just a representation of how CIL looks near the virtual machine (VM) level. When compiled the methods are stored in tables and the instructions are stored as bytes inside the assembly, which is a Portable Executable (PE). Generation A CIL assembly and instructions are generated by either a compiler or a utility called the IL Assembler (ILAsm) that is shipped with the execution environment. Assembled CIL can also be disassembled into code again using the IL Disassembler (ILDASM). There are other tools such as .NET Reflector that can decompile CIL into a high-level language (e. g. C# or Visual Basic). This makes CIL a very easy target for reverse engineering. This trait is shared with Java bytecode. However,