Generics

Learn

Existing chapters for this concept.

• Generics

  Core Java

  Compile-time safety; removes casts; enables better APIs. PECS: Producer Extends, Consumer Super.

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See it in code

Existing Java examples.

• core 20 Generics Demo

  Core Java · pkg1core/core20GenericsDemo.java · pkg1core · core20GenericsDemo.java

  - Generics give compile-time type safety and remove casts. - Type erasure: generic type info is removed at runtime. - PECS: Producer Extends, Consumer Super.…

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Prepare

Existing interview questions.

• What is generics erasure?

  Core Java — Interview Questions (200+)

  Clear naming, small methods, immutability, proper exceptions, tests, and idiomatic APIs.

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• Generics — Interview Questions (60+)

  Generics — Interview Questions (60+)

  Use bounded wildcards on input params (PECS), exact types on outputs.

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• Why generics?

  Generics — Interview Questions (60+)

  Compile-time type safety and fewer casts.

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• Why can't you create a generic array?

  Generics — Interview Questions (60+)

  Erasure makes array store checks unsound.

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• What is a generic method?

  Generics — Interview Questions (60+)

  A method with its own type parameters.

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• record generic?

  Java 9–21 Features — Interview Questions (95+)

  infers raw-ish; specify generic.

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• Generic type erasure reflection?

  Reflection & Annotations — Interview Questions (72+)

  Panama native interop.

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Java versions

• Generics

  Java 5

  Java 5. import static members.

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