Java如何选择使用哪个构造函数？

Question

I am not able to understand the output of the following program.

public class Confusing {

    private Confusing(Object o) {
        System.out.println("Object");
    }

    private Confusing(double[] dArray) {
        System.out.println("double array");
    }

    public static void main(String[] args) {
        new Confusing(null);
    }
}

The correct output is "double array". WHy was this constructor chosen as more specific than the other when both can accept null?

Answer 1

尽管两个构造函数都可以接受null ，但double[] 继承自java.lang.Object ，因此更具体。

Answer 2

The challenge of compiling dynamically typed languages is how to implement a runtime system that can choose the most appropriate implementation of a method or function — after the program has been compiled. Treating all variables as objects of Object type would not work efficiently.

Hence, choosing the specific one over Object .