Final vs Finalize in Java: Key Differences Explained
final is a Java keyword that marks a variable, method, or class as unchangeable after initialization; finalize is a protected method in java.lang.Object called by the garbage collector before reclaiming an object.
Devs type final daily for constants, yet stumble when cleanup is needed. “final” feels like “done,” so they assume finalize is the twin for releasing resources—confusing a compile-time lock with a runtime hook.
Key Differences
final prevents reassignment or extension at compile time and is enforced by the compiler. finalize is an overrideable method invoked by the JVM’s garbage collector at an unpredictable time—never guaranteed to run.
Which One Should You Choose?
Mark fields, parameters, and classes as final to express intent and immutability. Never rely on finalize; prefer try-with-resources or explicit cleanup methods for predictable resource management.
Examples and Daily Life
Store a constant tax rate: final double TAX = 0.07;. Close a file safely with try-with-resources instead of overriding finalize—it’s like locking your car (final) versus hoping the valet will close the windows (finalize).
Can I force finalize to run?
No. You can call System.gc() to suggest garbage collection, but finalize execution remains unreliable and is deprecated since Java 9.
Does final improve performance?
Yes. The JIT can inline final variables and methods, making code faster and clearer.
What replaced finalize?
Use AutoCloseable with try-with-resources or explicit close() methods for deterministic cleanup.