.NET Interview Questions 4 th Edition By Shivprasad ... - A2Z Dotnet

(A) What are different types of JIT?
JIT compiler is a part of the runtime execution environment.
In Microsoft .NET there are three types of JIT compilers:
• Pre-JIT: - Pre-JIT compiles complete source code into native code in a single
compilation cycle. This is done at the time of deployment of the application.
• Econo-JIT: - Econo-JIT compiles only those methods that are called at runtime.
However, these compiled methods are removed when they are not required.
• Normal-JIT: - Normal-JIT compiles only those methods that are called at runtime.
These methods are compiled the first time they are called, and then they are stored in
cache. When the same methods are called again, the compiled code from cache is used
for execution.
(B) What are Value types and Reference types?
Value types directly contain their data that are either allocated on the stack or allocated in-line in
a structure. So value types are actual data.
Reference types store a reference to the value's memory address, and are allocated on the heap.
Reference types can be self-describing types, pointer types, or interface types. You can view
reference type as pointers to actual data.
Variables that are value types each have their own copy of the data, and therefore operations on
one variable do not affect other variables. Variables that are reference types can refer to the same
object; therefore, operations on one variable can affect the same object referred to by another
variable. All types derive from the System. Object base type.
(B) What is concept of Boxing and Unboxing ?
Boxing and unboxing act like bridges between value type and reference types. When we convert
value type to a reference type it’s termed as boxing. Unboxing is just vice-versa. When an object
box is cast back to its original value type, the value is copied out of the box and into the
appropriate storage location.
Below is sample code of boxing and unboxing where integer data type are converted in to object
and then vice versa.
int i = 1;
object obj = i; // boxing
int j = (int) obj; // unboxing
(B) What is the difference between VB.NET and C#?
Well this is the most debatable issue in .NET community and people treat languages like religion.
It is a subjective matter which language is best. Some like VB.NET’s natural style and some like
professional and terse C# syntaxes. Both use the same framework and speed is very much
equivalents. Still let us list down some major differences between them:-
Advantages VB.NET:-
• Has support for optional parameters that makes COM interoperability much easy.