Question

I was wondering, what is there any different, on various ways to initialize static final variable?

private static final int i = 100;

or

private static final int i;
static {
    i = 100;
}

Is there any different among the two?

Answer 1

If you’re only setting variables, both forms are equivalent (and you should use the former as it is more readable and succinct).

The static {} form exists for cases where you also need to execute statements other than variable assignments. (Somewhat contrived) example:

private static final int i;
static {
    establishDatabaseConnection();
    i = readIntFromDatabase;
    closeDatabaseConnection();
}