If you run the following Groovy code, the assertion passes
def foo(a, b) {
a + b
}
assert 'aaabbb' == foo(['aaa', 'bbb'])
This suggests that if a method is called with a List parameter that contains X elements, then the List will be spread and a method with X arguments will be invoked.
Of course, this will only happen if there isn’t a method defined with a single parameter of type List (or ancestor thereof).
I only discovered this quite recently when reading another SO Groovy answer. I’ve never seen it mentioned in the Groovy docs, release notes, or books. Is it a hidden feature, a bug, or just something I’ve missed?
Going to be removed in Groovy 2 apparently:
http://groovy.329449.n5.nabble.com/removing-features-in-Groovy-2-td4422494.html
JT’s first on the to-remove list and it seems everyone (with clout) on Groovy User agrees.