snr :
What is the difference between the following method references,
BiPredicate<List<String>,String> contains1 = List<String>::contains;
BiPredicate<List<String>,String> contains2 = List::<String>contains;
BiPredicate<List<String>,String> contains3 = List<String>::<String>contains;
Do the cases have special names? Is there any example similar to the usage?
Eugene :
First of all, that is called a type witness (in the official Oracle Tutorial) or TypeArguments (in the JLS Sec 15.12) and you are effectively helping the compiler with such constructs.
One example:
private static void test(Callable<Object> call) {
}
private static void test(Runnable run) {
}
static class Gen<T> {
}
And call it via test(Gen::new); (this will fail, never mind why), but the point is that you add a type witness to help the compiler, so this would work
test(Gen<String>::new);
So when you write List<String>, you have added a type witness for the target type - List that is; in the second case you are adding one for the method contains - but it's not generic, so it is ignored.