What are the Key Differences Between Java 12 and 17?

Java 15 introduced Text Blocks which are super useful for handling multi-line strings. It simplifies code significantly, especially when working with JSON or SQL.

If you're looking for what matters most in production since Java 12, here are the highlights:

- **Virtual Threads (Loom)**: This is a game changer! It allows handling over a million concurrent requests with ease, effectively cutting infrastructure costs by half when used in frameworks like Quarkus or Spring.
- **Pattern Matching**: Since its introduction, it has dramatically reduced complex if-else structures.
- **Foreign Function API**: This has pretty much replaced JNI for native code interaction and is gaining traction in Android and desktop applications.
- **Garbage Collection Improvements**: Libraries like Gen ZGC and Shenandoah have made huge strides with pause time improvements, useful especially in finance and gaming apps.

Java 14 introduced significant features as well, like records which are now widely used in production for defining data classes succinctly. Pattern matching for 'instanceof' is also helping developers write cleaner and more concise code.

Records, sealed classes, and pattern matching are definitely big features that make coding in a functional style much easier. Those are commonly used in real-world applications to simplify code and enhance readability.

Make sure to check out the Java Enhancement Proposals (JEPs) for more detailed insights on each version's changes. Java 17 has become the minimum version in many environments now, and while newer versions are emerging, understanding 17 is still essential.