final static 和 static final 的区别

Question

I found a code where it declared code like

private final static String API_RTN_SUCCESS = "0";
private final static String API_RTN_ERROR = "1";

public static final String SHARED_PREFERENCE_CONFIG = "shared_preference_config";
public static final String STARTUP_SETTING_KEY = "startup_setting";

What is the difference between them or are they same? Or does it differ for private or public ?

Answer 1

No difference at all. According to 8.3.1 - Classes - Field Modifiers of the Java Language Specification ,

If two or more (distinct) field modifiers appear in a field declaration, it is customary, though not required, that they appear in the order consistent with that shown above in the production for FieldModifier.

For fields, the said production lists the modifiers in this order:

@Annotation public protected private static final transient volatile

And for methods:

@Annotation public protected private abstract static final synchronized native strictfp

Answer 2

They are the same. The order of modifiers is not significant. And note that the same rule applies in all contexts where modifiers are used in Java.

However, most Java style guides recommend/mandate the same specific order for the modifiers. In this case, it is public static final .

Answer 3

private static final String API_RTN_ERROR= "1";
private final static String API_RTN_ERROR= "1";
static private final String API_RTN_ERROR= "1";
static final private String API_RTN_ERROR= "1";
final static private String API_RTN_ERROR= "1";
final private static String API_RTN_ERROR= "1";

even all above are same the position of first three is intercangeable.

Answer 4

They are same,

private final static String API_RTN_ERROR = "1";

private static final String API_RTN_ERROR= "1";

Answer 5

No difference logically and no technical impact.

only issue is that sonarqube will report Code Smell if you use in this order

private final static <Type> <variable_name> = <value>;

Hence recommendation is to use:

private static final <Type> <variable_name> = <value>;

The Java Language Specification recommends listing modifiers in the following order:

1. Annotations
2. public
3. protected
4. private
5. abstract
6. static
7. final
8. transient
9. volatile
10. synchronized
11. native
12. strictfp

Note following this convention has no technical impact, but will reduce the code's readability because most developers are used to the standard order.

Answer 6

What is the difference between them or are they same?

If you are talking about changing order of static and final then yes they are same.

does it differ for private or public?

No, you can use any order in private and public. Just difference is private variables will not be accessible outside of class directly.

Answer 7

This is just a convention or a practice people follow to keep coding style consistent. It improves the readability. so preferred way of writing this is

private static final <Type> <variable_name> = <value>;

Answer 8

it's the same, of course. it only depends on your habits and preference:-). I use public static final order for members and methods too