What are generics in Java?

Generics allow classes, interfaces, and methods to operate on types specified as parameters, providing type safety at compile time without requiring casts. Example: List<String> is a list that can only hold Strings — trying to add an Integer would be a compile error. Before generics (Java 1.4), collections held Object references requiring explicit casts everywhere and causing runtime ClassCastException. Generic methods: public <T> T getFirst(List<T> list). Bounded type parameters: <T extends Comparable<T>> restricts T to types that are comparable. Due to type erasure, generic type information is removed at compile time — at runtime, List<String> is just List.