Java FAQ: Top Questions
21. What are generics in Java?
Generics in Java allow classes, interfaces, and methods to operate on objects of specified types, providing type safety and eliminating the need for explicit casting. Introduced in Java 5, generics enhance code reusability and compile-time type checking.
Key points about generics:
-
Type Parameters:
Defined using angle brackets (e.g.,
List<String>). - Type Safety: Prevents runtime errors by enforcing type constraints at compile-time.
- Generic Classes/Methods: Can define classes or methods with type parameters.
-
Bounded Types:
Restrict type parameters (e.g.,
<T extends Number>). -
Wildcards:
Use
?for unknown types (e.g.,List<?>).