automatic memory management allocates and releases memory prevents memory leaks and accessing dead objects provides memory safety virtual memory space defragments/compacts memory heap have 3 generations 0 - for new objects; 1 - for objects that lives through GC from 0 2 - for long living objects from 1 and 0 also Large Objects Heap (LOH) for big objects like arrays over 85,000 bytes Further read:
https://learn.microsoft.com/en-us/dotnet/standard/garbage-collection/fundamentals?source=recommendations
allows for matching signatures of delegates and method groups
to assign to delegates from method that returns more derived types - covariance
to assign to delegates from method that returns less derived types - contravariance
Covariance and Contravariance are supported in Generics for implicit conversions for type parameters
allows method to have more derived return type than defined by generic type parameter of the interface
this allows implicit conversions from one generic interface to another (from IEnumerable<string> to IEnumerable<object> even if first does not inherits from second)
allows generic types to have less derived argument types than specified by the generic parameter of the interface (implementation of IEqualityComparer<BaseClass> can be implicitly converted to IEqualityComparer<DerivedClass> because IEqualityComparer.Equals is contravariant)
implicit conversions works for interfaces but not classes that implement from those interfaces (i.e. this won’t work List<Object> list = new List<String>())
Assignment compatibility is when object of a more derived type is assigned to an object of a less derived type.
sequential collection of chars immutable max 2GB or about 1 billion characters reference type are interned - CLR saves memory by maintaining a table, called the “intern pool”, that contains a single reference to each unique literal string declared or created programmatically in your program. Further read:
https://learn.microsoft.com/en-us/dotnet/api/system.string?view=net-7.0 https://learn.microsoft.com/en-us/dotnet/api/system.string.intern?view=net-6.0#remarks
ref struct type can not be used as object field.
Further read:
`ref struct` types https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/ref-struct
added as part of C# 7.2. defined with ref struct StructName always on the stack never part of heap cannot be element of an array cannot be field type of reference type can’t implement interfaces can’t be boxed can’t be type argument can’t be captured by closure of lambda or local function can’t be used in async methods can’t be used in iterators Further read:
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/ref-struct
Reference types:
passed via reference reside on the heap subject to GC inherits from System.Object Value types:
passed via value reside on the stack, CPU registers or the heap no subject to GC inherits from System.ValueType Further read:
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/reference-types https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/value-types https://www.infoworld.com/article/3043992/a-deep-dive-value-and-reference-types-in-net.html
shared type system across all .net languages primitives data types library 5 kind of types: classes structures enumerations interfaces delegates Further read:
https://learn.microsoft.com/en-us/dotnet/standard/base-types/common-type-system
provides a pool of threads can be used to execute tasks post work items process asynchronous I/O process timers Further read:
https://learn.microsoft.com/en-us/dotnet/api/system.threading.threadpool?view=net-6.0
simplify process of adding parallelism and concurrency to application scales concurrency automatically data parallelism task based async programming data flow Further read:
https://learn.microsoft.com/en-us/dotnet/standard/parallel-programming/task-parallel-library-tpl
In short:
it will not work because it requires boxing and boxing will create new object for reference in lock every time code is executed so lock statement will not prevent anything.
Further read:
https://intellitect.com/blog/locking-a-block-of-code-with-an-integer/
