Can a generic class be instantiated without specifying an actual type argument?
when a generic class is instantiated without specifying an actual type argument, the generic class is being used… let Point be a generic type. We want to write a method that takes as parameter Point objects whose type parameter is the Number class, or any superclass of Number.
Why can you not instantiate objects of the template type in generics?
Second, you can’t instantiate T because Java implements generics with Type Erasure. Almost all the generic information is erased at compile time. Basically, you can’t do this: T member = new T();
How to instantiate a passed generic type inside a?
If you want to avoid that – and in a factory pattern you sometimes force the others to go through your factory method and not directly through the constructor – then the alternative is to use reflection ( Activator.CreateInstance…) and keep the default constructor private. But this comes with a performance penalty, of course.
How are generic types different from constructed types?
The principle difference is that a generic type has a list of Type objects representing its generic type parameters. The first procedure in this section examines generic types. You can create a Type object that represents a constructed type by binding type arguments to the type parameters of a generic type definition.
How can I get information about generic types?
Information about generic types is obtained in the same way as information about other types: by examining a Type object that represents the generic type. The principle difference is that a generic type has a list of Type objects representing its generic type parameters. The first procedure in this section examines generic types.
Do you have to have a constructor for a generic method?
Without specifying the type must have a constructor: To extend on the answers above, adding where T:new () constraint to a generic method will require T to have a public, parameterless constructor.