Initialization on demand for multiple static variables without static nested classes?

Question

I want to have a class with multiple static variables that will only be initialized on demand.

public class Messages {
    public static final String message1 = init1();
    public static final String message2 = init2();
}

So when somewhere in the code I reference Messages.message1 I want only init1() to be called. If later I access Messages.message2 then only at that time should init2() be called.

I know it is possible to do this with the Initialization-on-demand holder idiom, but this is cumbersome if you have lots of fields.

Is there another way?

Similar to what you linked, instead of referencing a field, invoke a method. The method will return (and cache) the initialized value. — Sotirios Delimanolis, Oct 26 '14 at 15:46

score 2 · Answer 1 · edited Oct 26 '14 at 16:05

Most common way for lazy initialization is initialization in getter method:

public class Messages {
    private static String message1;
    public static String getMessage1() {
        if (message1 == null)
            message1 = init1();
        return message1;
    }
}

If you want exactly public final static fields then there is no way to achieve separate initialization for them in Java. All class members are initialized together.

Initialization on demand for multiple static variables without static nested classes?

1 Answers1