Name clash: Two methods have the same erasure

[Jay Rex]

I have two methods that I want to overload:

private void saveList(List<Product> productList) {
    // Write file by looping through productList
}

private void saveList(List<Inventory> inventoryList) {
    // Write file by looping through inventoryList
}

The compiler error I encounter:

error: name clash: saveList(List<Inventory>) and saveList(List<Product>) have the same erasure
    private void saveList(List<Inventory> inventoryList) {
                 ^
1 error

If I rename the one method, the code compiles, but I want to know why this is considered a name clash.

Why is the code above not an example of method overloading where the data type of the parameters is different?

How do I fix this, so that I can overload these methods?

[Campbell Ritchie]

That isn't overloading. They both have the signature saveList(List). Remember that generic information is removed at runtime, so the compiler cannot distinguish those two methods.
I am not sure what the correct answer is because you haven't provided enough information about the two methods. I am a bit suspicious, however, that you are acting outwith the List's original owning object, which means you are breaching the single responsibility principle. I have found a few places where you can find out about that: 1 2 and enclosed links. If there is an object with those Lists in, maybe that object should be responsible for maintaining those Lists. Unless you have a generic list saving utility, consider moving those methods elsewhere.

[Junilu Lacar]

It's because of type erasure: https://docs.oracle.com/javase/tutorial/java/generics/erasure.html

And I think you might have gotten it backwards there, Campbell. Generic types are used by the compiler to provide tighter type checking. Type erasure will replace the generic types with ordinary types (classes, interfaces) and methods, typecasts to preserve type safety, or bridge methods to preserve polymorphism. It's the runtime that has no idea of generics, so the error is the compiler basically saying: "Oops, when I apply type erasure these two methods turn out to have the same exact signature. That's not going to work for the JVM."

[Jay Rex]

Thanks Campbell and Junilu.

Note to self: Use the search function before posting, as this has been covered already

[Campbell Ritchie]

Jay Rex wrote:Thanks Campbell and Junilu. . . .

That's a pleasure And sorry that I worded my reply so badly.