What is the best way to implement constants in Java?

java constants
mk. picture mk. · Sep 15, 2008 · Viewed 721.9k times · Source

I've seen examples like this: 

public class MaxSeconds {
   public static final int MAX_SECONDS = 25;
}

and supposed that I could have a Constants class to wrap constants in, declaring them static final. I know practically no Java at all and am wondering if this is the best way to create constants.

Answer

jjnguy picture jjnguy · Sep 15, 2008

That is perfectly acceptable, probably even the standard.

(public/private) static final TYPE NAME = VALUE;

where TYPE is the type, NAME is the name in all caps with underscores for spaces, and VALUE is the constant value;

I highly recommend NOT putting your constants in their own classes or interfaces.

As a side note: Variables that are declared final and are mutable can still be changed; however, the variable can never point at a different object.

For example:

public static final Point ORIGIN = new Point(0,0);

public static void main(String[] args){

    ORIGIN.x = 3;

}

That is legal and ORIGIN would then be a point at (3, 0).

Related questions

Storing integer values as constants in Enum manner in java

I'm currently creating integer constants in the following manner. public class Constants { public static int SIGN_CREATE=0; public static int SIGN_CREATE=1; public static int HOME_SCREEN=2; public static int REGISTER_SCREEN=3; } When i try to do this in enum …

Read More
Why is there no Constant feature in Java?

I was trying to identify the reason behind constants in Java I have learned that Java allows us to declare constants by using final keyword. My question is why didn't Java introduce a Constant (const) feature. Since many people say …

Read More
How can I get a resource content from a static context?

I want to read strings from an xml file before I do much of anything else like setText on widgets, so how can I do that without an activity object to call getResources() on?

Read More