Java "..." expression

Question

I'm interested in what is this '...' expression in some codes, for example:

public static void main(String... args){
   //code here
}

This is valid (maybe lambda, i'm not sure).

I find it in Spring's Sort file too:

public Sort(Sort.Order... orders) {
    this(Arrays.asList(orders));
}

Somebody can help me?

this are [varargs](http://stackoverflow.com/questions/766559/when-do-you-use-varargs-in-java) and another [SO question](http://stackoverflow.com/questions/1656901/varargs-and-the-argument) — SomeJavaGuy, Sep 23 '15 at 09:01

score 3 · Accepted Answer · answered Sep 23 '15 at 09:04

This idiom is not a lambda, it's called varargs (short for variable arguments) and it's there since Java 5.

The functionality allows you to take an indeterminate number of parameters of the same type (or sub-types) at the end of a method's signature, once per method signature.

The arguments can then be handled as an array of that type.

score 1 · Answer 2 · answered Sep 23 '15 at 09:04

1

The "..." is "varargs": It accepts an arbitrary amount of String in first example and Orders in 2nd one. Those methods does also accept arrays.

answered Sep 23 '15 at 09:04

dermoritz

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Java "..." expression

2 Answers2