Decoding Java Generics: Type Safety, Wildcards, and How They Work Internally

"Learn how generics work behind the scenes, from type erasure to synthetic bridge methods, and how to leverage wildcards for flexible design. I have also made a quiz, which you should take after reading this blog to test your understanding of java generics. Photo by Arnold Francisca on Unsplash Table of content : Why Generics was introduced? What is generics ? Wildcards in Generics How generics works internally Exception handling with generics Synthetic Bridge Method Quiz On Readers demand Conclusion"

"Exception handling with generics Synthetic Bridge Method Quiz On Readers demand Conclusion Why Generics was introduced? Before Java5, Collections like Hashset, ArrayList, LinkedList etc were designed to store objects of Object' type, which was giving us the flexiblity to store any type of object. The following is an example on how it works : But this flexibility came with some consequences :"

Generics enable compile-time type safety for parameterized types such as collections and reduce runtime ClassCastException risk. Wildcards like ? extends and ? super express covariance and contravariance for flexible API design. At runtime type parameters are erased by the compiler through type erasure, with casts inserted where needed and synthetic bridge methods generated to preserve polymorphism after erasure. Generics impose constraints such as prohibition of generic exception types and generic array creation. Proper use of wildcards, bounded type parameters, and awareness of erasure and bridge methods allows safer, more flexible Java code when working with collections and generic APIs.

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