Update Java Minimum Version to JDK8

[martinei]

Stateless4J introduces a number of (Functional) Interfaces that are present in a similair form in the jdk since java 8 (Action1 -> Consumer, Action2 -> BiConsumer, Func -> Supplier, Func2 -> Function, Func3 -> BiFunction, FuncBoolean -> BooleanSupplier).

What do you think about updating to a more recent java, removing the duplicates and renaming some of the other interfaces to match the JDK Naming (e.g. Func4 -> TriFunction, Action3 -> TriConsumer)? Using the familiar names would make it easier for the reader.

[Ktar5]

I'm not entirely sure about this, though I have thought about it. I'll leave this issue open for a while and see if there is any other expressed interest in this. If so, it'll happen, if not-- it's a non-issue.

[binkley]

I found this project through a GitHub issue in JUnit (junit-team/junit5#48 (comment)).

Given that Java 11 is the LTS version, and Java 13 is heading our way ... what is the maintenance status of this project? :)

[ezaquarii]

@martinei Since I took the maintainership, I'm open to modernization proposals. If you are interested in helping out, let me know.

[ezaquarii]

@binkley This project has been almost abandoned, but since I'm using it in other projects, I took ownership of it now. I'll try to gradually make it in better shape. Let me know if you are interested in helping out.

[ezaquarii]

There are 2 reasons why we'd like to keep old interfaces:

1. existing users will be forced to migrate their solutions
2. Android runtime pre API-24 still does not support many JDK8 classes and this is substantial developer demographic I'd like to support

I'll bump language to Java8 to enable use of language features, but I do not plan to refactor APIs in the near future.