generics | Package generics is the true way

Assuming what I mentioned in my comment on your question, the fix is just to simplify your FieldWithConfidence type significantly. Right now it is trying to add a number of additional levels of structure beyond what you seem to want. Here is a version of that type that works as I think you intend:

In the first case:

You need to do things slightly different when you're defining a struct, and when you're instantiating a struct.

When you write:

If you want to go strictly by the book and the common convention, you may go for below. Note in your writeup you have already mentioned that T should be used for Type and S for Second Type etc..

public abstract class AbstractService

However, if you want to make it more explicit and avoid any possible confusion with Second Types etc.., you could use convention like below which explains the context of usage as well.

public abstract class AbstractService

Optionally, you may also want to make these look like classes to depict more specific inputs, and go for something like below.

public abstract class AbstractService

All options would work, but its usually driven by the convention being followed in your project/enterprise. First one is probably what you are looking for here.

Please note, while Java will not be unhappy with 2nd and 3rd options mentioned here, if you are a stickler for Code Quality and Static Analysis, Sonar will be unhappy with using such names. It expects you to use either S, T convention, or you may also choose T1, T2 to indicate the two types.

public abstract class AbstractService

Between S, T and T1, T2, you should probably go for the S, T convention. Sonar expects type names to follow the pattern '^[A-Z][0-9]?$'

Hope this helps you decide. If you are confused with options, you can simply go with the 1st one.

Think of the parameter as a constructor instead of a class:

Due to type erasure, you cannot do this without passing the concrete class to the constructor. Or, to avoid having to use reflection to find and call the constructor, it would be cleaner to give the constructor a function parameter for constructing the ViewHolder, so you can just pass the a constructor reference.

Example:

You can use SerializerMethodField and calculate it. Get the authenticated user and check if the serialized user is in the blocked list.

The DEFAULT_PAGINATION_CLASS setting should be a string not a tuple/list

The point of const generics is that the size of the array is known at compile-time. If you want a runtime-known size, then that's what Vec is for. Consider