What is the ellipsis (…) for in this method signature?

Question

In the App Engine docs, what is the ellipsis (JID...) for in this method signature?

public MessageBuilder withRecipientJids(JID... recipientJids         


        

Answer 1

It means that the method accepts a variable number of arguments ("varargs") of type JID. Within the method, recipientJids is presented.

This is handy for cases where you've a method that can optionally handle more than one argument in a natural way, and allows you to write calls which can pass one, two or three parameters to the same method, without having the ugliness of creating an array on the fly.

It also enables idioms such as sprintf from C; see String.format(), for example.