Can a java lambda have more than 1 parameter?

Question

In Java, is it possible to have a lambda accept multiple different types?

I.e: Single variable works:

    Function  adder = i         


        

Answer 1

It's possible if you define such a functional interface with multiple type parameters. There is no such built in type. (There are a few limited types with multiple parameters.)

@FunctionalInterface
interface Function6 {
    public Six apply(One one, Two two, Three three, Four four, Five five);
}

public static void main(String[] args) throws Exception {
    Function6, Character> func = (a, b, c, d, e) -> 'z';
}

I've called it Function6 here. The name is at your discretion, just try not to clash with existing names in the Java libraries.

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There's also no way to define a variable number of type parameters, if that's what you were asking about.

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Some languages, like Scala, define a number of built in such types, with 1, 2, 3, 4, 5, 6, etc. type parameters.