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Great job learning about generics! In this lesson we’ve covered how:

  • Generics help us make generic, scalable code.
  • The diamond operator (<>) is used to define generic classes, interfaces, or methods.
  • Generics provide compile-time type safety and bug detection as opposed to raw types.
  • We can create multiple bound generic classes, interfaces, and methods.
  • Wildcards are used to define unknown types.
  • To Add upper bounds to type parameters and wildcards.
  • To Add lower bounds to wildcards.

Knowing these topics will help you create scalable, type safe code, and give you a better understanding of the Java collections framework (we’ll learn about this later).


Use the workspace to continue exploring generics. Some ideas to try out:

  • Exploring super and extends on wildcard types. Specifically what type of references can you read and write when using extends and super.
  • Multiple upper bounds when using type parameters.

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