What is the concept of erasure in generics in Java?

Question

What is the concept of erasure in generics in Java?

Answer 1

As I understand it (being a .NET guy) the JVM has no concept of generics, so the compiler replaces type parameters with Object and performs all the casting for you.

This means that Java generics are nothing but syntax sugar and don't offer any performance improvement for value types that require boxing/unboxing when passed by reference.