Java - 将数组直接传递给构造函数，而不是作为变量

Question

Let's take the following example:

public class Test {
    public void main(String[] args) {
        int[] someInts = {1, 2, 5};
        new Dummy(1, someInts, "Hello");    //works
        new Dummy(1, new int[] {1, 2, 5}, "Hello"); //works
        new Dummy(1, {1, 2, 5}, "Hello");   //fails
        new Dummy(1, [1, 2, 5], "Hello");   //fails
    }

    public class Dummy {
        Dummy(int someNumber, int[] someArray, String message) {

        }
    }
}

For both failing lines, Eclipse says: "The constructor Test.Dummy(int, int, int, int, String) is undefined"

Firstly, I don't understand why it doesn't recognize the array as an array (in the failing lines only).

Secondly, why can I not pass the array directly into the constructor, but instead have to create a variable to pass it?

And thirdly, is there a way to create a constructor which takes something like that line in question, meaning without a variable or a new int[] {...} statement?

If someone knows a better way to formulate this in the title, feel free to improve it.

Answer 1

As said, that's how you create an array literal in the general case.

You could replace the array with a int... array varargs parameter, but then you'll need to make it the last parameter.

Dummy(int someNumber, String message, int... someArray) {}
new Dummy(1, "Hello", 1, 2, 5);

Answer 2

new Dummy(1, {1, 2, 5}, "Hello"); , you can only use {} syntax for array initialization . use new Dummy(1,new int[] {1, 2, 5}, "Hello");