Can Java Annotations Use Arrays or Constants as Parameter Values?

Constant Values in Java Annotations

It is common practice in Java to define interfaces that store arrays of constants to be used as annotation parameters. For example, you may have an interface like this:

public interface FieldValues {
   String[] FIELD1 = new String[]{"value1", "value2"};
}

When annotating classes, you might want to use these constants as parameter values, something like this:

@SomeAnnotation(locations = {"value1", "value2"})
public class MyClass {
   ....
}

However, this approach requires specifying the string values in every annotation instance. It would be more convenient to use the constants directly:

@SomeAnnotation(locations = FieldValues.FIELD1)
public class MyClass {
   ....
}

Unfortunately, Java does not allow using arrays or constants as annotation parameter values. This is because annotations are resolved at compile time, and only primitive values or strings can be used as compile-time constants.

Therefore, there is no direct way to achieve the desired behavior in Java. The array in FieldValues is not truly constant, as its elements can be modified at runtime by any code that has access to it. To ensure true immutability, you could consider using an immutable class to wrap the string values.

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