Reified

With reified generics we can avoid type-erasure that comes with java-generics

Type Erasure

• Type erasure means that whenever a code is compiled every generic param is erased and replaced with specific object type.
• So during the runtime we don't have any generic type arguments.
• So JAVA byte code does not know generics.

code(With error)

fun <T : Any> newInstance(clazz:Class<T>) {
    val clazz = T::class.java
}

error

code(With Solution)

inline fun <reified T : Any> newInstance() {
    val clazz = T::class.java
}

Marking with reified keyword

• When you mark your generic type with a reified keyword, You will be able to access it during the runtime.
• When using the reified keyword, it is necessary to mark the function as inline, As it enables the substitution of the inline keyword with code

Summary

• Problem: When we use generics in kotlin and try to cast a Type in a function, The Type erasure happens and the compiler throws an error
• Solution: We can just mark the left of the type T with reified and make that generic function inline so that the code is substituted at compile time so the appropriate type would be available.
• Usecase: When we use Gson to convert to JSON, Say this conversion function we make as generic so that it works with any class