- Generics - Home
- Generics - Overview
- Generics - Environment Setup
- Examples - Generic Classes
- Generics - Generic Classes
- Type Parameter Naming Conventions
- Generics - Type inference
- Generics - Generic Methods
- Generics - Multiple Type Parameters
- Generics - Parameterized Types
- Generics - Raw Types
- Examples - Bounded Type Parameters
- Bounded Type Parameters
- Generics - Multiple Bounds
- Examples - Collections
- Generics - Generic List
- Generics - Generic Set
- Generics - Generic Map
- Examples - Wild Cards
- Upper Bounded Wildcards
- Generics - Unbounded Wildcards
- Lower Bounded Wildcards
- Generics - Guidelines for Wildcards
- Type Erasure
- Generics - Generic Types Erasure
- Generics - Bound Types Erasure
- Unbounded Types Erasure
- Generics - Generic Methods Erasure
- Restrictions on Generics
- Generics - No Primitive Types
- Generics - No Instance
- Generics - No Static field
- Generics - No Cast
- Generics - No instanceOf
- Generics - No Array
- Generics - No Exception
- Generics - No Overload
- Generics Useful Resources
- Generics - Quick Guide
- Generics - Useful Resources
- Generics - Discussion
Java Generics - Type Erasure
Generics are used for tighter type checks at compile time and to provide a generic programming. To implement generic behaviour, java compiler apply type erasure. Type erasure is a process in which compiler replaces a generic parameter with actual class or bridge method. In type erasure, compiler ensures that no extra classes are created and there is no runtime overhead.
Type Erasure rules
Replace type parameters in generic type with their bound if bounded type parameters are used.
Replace type parameters in generic type with Object if unbounded type parameters are used.
Insert type casts to preserve type safety.
Generate bridge methods to keep polymorphism in extended generic types.
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