小编Ahm*_*mad的帖子

例如一个类:

//class1
class A {
    private A() {  } // why would I make it private?
    public A(int) {  } //why isn't it implicitly public?
}
//class2
class B {

    public static void main(String[] args) {
        //A a = new A();
    }
}

构造函数实例化一个类,为什么它有访问修饰符？是否有必要声明构造函数是私有的？