Make private methods final?

java final
deamon picture deamon · Dec 31, 2009 · Viewed 17.6k times · Source

Is it beneficial to make private methods final? Would that improve performance?

I think "private final" doesn't make much sense, because a private method cannot be overridden. So the method lookup should be efficient as when using final.

And would it be better to make a private helper method static (when possible)?

What's best to use?

  private Result doSomething()
  private final Result doSomething()
  private static Result doSomething()
  private static final Result doSomething()

Answer

Tom Hawtin - tackline picture Tom Hawtin - tackline · Dec 31, 2009

Adding final to methods does not improve performance with Sun HotSpot. Where final could be added, HotSpot will notice that the method is never overridden and so treat it the same.

In Java private methods are non-virtual. You can't override them, even using nested classes where they may be accessible to subclasses. For instance methods the instructoin to call privates is different from that used for non-privates. Adding final to private methods makes no odds.

As ever, these sort of micro-optimisations are not worth spending time on.

Related questions

How does the "final" keyword in Java work? (I can still modify an object.)

In Java we use final keyword with variables to specify its values are not to be changed. But I see that you can change the value in the constructor / methods of the class. Again, if the variable is static then …

Read More
What is the point of "final class" in Java?

I am reading a book about Java and it says that you can declare the whole class as final. I cannot think of anything where I'd use this. I am just new to programming and I am wondering if programmers …

Read More
private final static attribute vs private final attribute

In Java, what's the difference between: private final static int NUMBER = 10; and private final int NUMBER = 10; Both are private and final, the difference is the static attribute. What's better? And why?

Read More