Thread: Static methods and variables

Hi,

Lately I've developed an interest in game developing and chosen libgdx as my library. So I was collecting resources and reading them. Someone gave me a link to a video (sadly I lost it with many many bookmarks), and the guy used static keyword more than I ever did.

While I was studying his code (typing to my IDE and altering it), I started to think about static keyword.

Static variables, I can understand. If you don't want to create an instance of a class just for a variable, you just make it static. Or if you want a variable to have the same value at any time in everywhere.
But what about static methods?

I went through my old codes (both practice codes and the codes I tried to make a good program) and I realized I almost never used static variables, let alone static methods.

So, why would one decide to use static method? And, what are some cases in which I could use static keyword?

static methods are often used for helper methods, that are stateless. E.g. a method that formats a Date into a String or builder methods, or whatever. Another classic case are the getInstance() methods from singletons.

Hmm... I guess I could use some static methods in some of my apps...

How does this compare to usual method in terms of performance and resource consuming?

Zero, nothing, nada. If that mattered, you have other severe bottlenecks. No need to worry about that, unless you plan to deploy applications on a toaster.

Thanks. That was soo clear

Originally Posted by beer-in-box

...So, why would one decide to use static method?

When the method will always be the same across any instance of the class.

Originally Posted by beer-in-box

...And, what are some cases in which I could use static keyword?

Take a "Temperature" class for example. The conversion from fahrenheit to celsius is always the same.

It can change over time, but what I meant was it is the same for every class at any given time, right? Until one of the classes changes its value...

Originally Posted by beer-in-box

It can change over time, but what I meant was it is the same for every class at any given time, right? Until one of the classes changes its value...

yes, for any number of instances of that class, they all share the same static variable