---
title: "jg k (@junggikim) | Hashnode"
description: "Java/Kotlin open source developer. Creator of java-refined."
url: "https://hashnode.com/@junggikim"
---

@junggikim

# jg k

@junggikim · Joined March 2026

### [Stop Writing if-checks: Refinement Types in Java 8+](https://junggikim.hashnode.dev/stop-writing-if-checks-refinement-types-java?utm_source=hashnode&utm_medium=feed)

The Code That Lives in Every Java Codebase Every Java developer has written this code. You have written this code. Probably this week. A method starts with five lines of null checks, blank checks, and range checks before a single line of business log...

9 min read · [junggikim.hashnode.dev](https://junggikim.hashnode.dev/stop-writing-if-checks-refinement-types-java?utm_source=hashnode&utm_medium=feed)

[Mar 17](https://hashnode.com/posts/stop-writing-if-checks-refinement-types-java/69b91e65125e4462c46db6bb)