Finally, final means final: A Deep Dive into Java Field Immutability

Per Minborg unpacks Java’s trusty but often misunderstood final keyword—showing how the JVM still has to assume some “final” fields might change, why that can slow you down, and how to use current JVM quirks to squeeze out better performance right now. You’ll get a clear view of compile-time guarantees versus actual JVM behavior, plus practical tips for writing faster, more predictable code.

Then we peek at the future: recent efforts to make final genuinely unchangeable, the roadmap for beefing up its guarantees, and Java’s new preview feature “Stable Value,” which offers the flexibility of mutable fields without giving up the speed of true immutability.

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