Are keys unique in resource bundles?

Question

What is the use of public final String[] getStringArray(String key) in ResourceBundle?
Aren't keys in properties files unique? Would this ever return more than one value? If not why does it return an array?

Answer 1

If you read carefully the documentation of ResourceBundle, its says that: -

Resource bundles belong to families whose members share a common base name, but whose names also have additional components that identify their locales.

Also: -

Resource bundles contain key/value pairs. The keys uniquely identify a locale-specific object in the bundle.

So, keys are only unique for a particular locale. In two different locale, you can have keys that are same. That is why the return type is String[].

And for the method - getStringArray: -

Gets a string array for the given key from this resource bundle or one of its parents.

Answer 2

The value in a ResourceBundle does not have to be a String, the value can be any Object. In this case you expect it to be a String[].

From the javadoc you linked:

Keys:

Resource bundles contain key/value pairs. The keys uniquely identify a locale-specific object in the bundle.

Values:

Keys are always Strings. In this example, the keys are "OkKey" and "CancelKey". In the above example, the values are also Strings--"OK" and "Cancel"--but they don't have to be. The values can be any type of object.