- https://docs.oracle.com/javase/8/docs/api/java/lang/package-summary.html
- https://www.baeldung.com/java-primitives-vs-objects
- Optional - The Mother of All Bikesheds by Stuart Marks
- https://github.com/aol/cyclops
- https://github.com/vavr-io/vavr
- https://projectreactor.io/docs/
- https://mermaidjs.github.io/mermaid-live-editor/
- https://mermaidjs.github.io/#/classDiagram
- https://www.manning.com/books/java-8-in-action
- https://jcp.org/en/jsr/detail?id=305
- https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/lang/
- https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/lang/NonNull.html
- https://projectlombok.org/features/NonNull