What limitations exist when using generics in a programming language?

In Java, generics have several limitations related to the implementation via type erasure:

• Lack of type information at runtime. Generic parameter types are erased, so they cannot be used with instanceof or to create objects of type T directly.

• Cannot create arrays of parameterized types. For example, new T[10] is prohibited.

• Primitive types cannot be used as parameters. Generics only work with object types (e.g., Integer instead of int).

• Restrictions on static fields and methods. Static members cannot use the type parameter because it does not exist at the class level.

• Cannot instantiate parameterized types with new.

Example of a limitation with array creation:

public class Box<T> {
    // Compilation error:
    // T[] array = new T[10];
}

These limitations are due to the fact that generics in Java are implemented through type erasure for backward compatibility.