Does Using the `final` Keyword in Java Enhance Performance?

How does the use of the final keyword in Java affect performance?

final String str = "abc"; // Example of using final with a string

The `final` keyword in Java is versatile, acting as a modifier for classes, methods, and variables. While its primary purpose is to establish immutability and restrict inheritance, it may also have implications on performance due to optimization opportunities for the Java Virtual Machine (JVM). Here's a detailed exploration.

final class MyFinalClass { 
    final void myFinalMethod() { 
        // logic here 
    } 
} // Example of using final with a class and method

Causes

• Using `final` with variables prevents reassignment, helping the compiler make optimizations.
• Marking methods as `final` can sometimes lead to inlining, which reduces method call overhead.
• Declaring classes as `final` prevents the creation of subclasses, offering potentially better memory allocation and access speed.

Solutions

• Use `final` for constants that should not change.
• Apply `final` to methods that should not be overridden to aid in performance optimization.
• Consider marking classes as `final` if you do not intend them to be extended.

Mistake: Misunderstanding that using `final` always leads to performance gains.

Solution: Understand that while `final` can help the JVM optimize, not all uses guarantee improved performance.

Mistake: Neglecting to use `final` for high-frequency method calls.

Solution: Consider marking frequently called methods as `final` to help the compiler optimize method calls.