Question

I have a class defined like so:
public class AddRecordsToolbar<D extends IDataSource<T>, T extends Serializable>
extends AbstractToolbar<D, T>

which my IDE IntelliJ IDEA declares as legal. It looks and feels wrong to me.
I want to declare it like this:
public class AddRecordsToolbar<D extends IDataSource<T extends Serializable>, T>
extends AbstractToolbar<D, T>
however that syntax is illegal thanks to something to do with Javas type erasure.

D extends IDataSource<T> is required by the superclass.
My Class is using Serializable to do a deep copy. Hence the T extends Serializable.

So now on to the Question: If I specify T extends Serializable as the second type parameter for my class will it still enforce T extends Serializable for D as well?

Answer 1

Answering to your question, yes its do.

The order of generic parameter it only in your mind.

If we would rephrase that implementation to:

public class AddRecordsToolbar<T extends Serializable, D extends IDataSource<T>> extends AbstractToolbar<D, T>

you will be not so surprised, and looks that the way it should be.

I will try to find the explanation for this in Java Language Specification (when it will work) but for now that the way it is.