Issue
I was researching creating a generic sprint webflux based HTTP client and ran across code
public <T> ResponseWrapper<T> makeRequest(URI uri, Class<T> clazz) {
is that the same as <T,ResponseWrapper<T>> I am not used to seeing two generic arguments on left hand side and not sure how to read/interpret it.
Is T required before ResponseWrapper<T> could you shorten it?
Solution
The first <T> (directly after public) declares a generic parameter for the method. ResponseWrapper<T> then uses that parameter to declare the method's return type.
You can read it as "this method is public, has a generic parameter T, and returns a ResponseWrapper<T>." Without declaring that generic parameter, you wouldn't be able to declare a return value of ResponseWrapper<T>: Java would tell you that it doesn't know what T is in this context. (Remember that T is also a perfectly valid class name — and Java doesn't want to guess at your intentions).
Note that if the class is also generic and has a T parameter, this method's <T> will declare a new parameter. That method-specific one is unrelated to the class's T, and will shadow it — basically making the class's T inaccessible.
Answered By - yshavit
Answer Checked By - Marilyn (JavaFixing Volunteer)
