Result, Either, Try, and Maybe monadic types for Java

Simplified polymorphic de/serialization of Java 17 sealed classes for Jackson

让 Java 1.8 也能像 Kotlin 一样使用 Sealed Class。Make Java 1.8 use Sealed Class like Kotlin

Includes Java 17 related features.

Algebraic Result type in Java 15+, return type for oprations that can fail

Testing the new features in Java 17

📚 Java language basics

a simple math expr evaluator