java - Does Class.getDeclaredConstructor return only public constructors?

Question

Going over the documentation for this method here: getDeclaredConstructor()

I could not see any reference of it returning only public constructors.

My problem is that I have the following piece of code:

protected BaseClass internalCreate(String className) throws Exception {

    Class<? extends BaseClass> classObj = Class.forName(className)
                    .asSubclass(BaseClass.class);

    Constructor<?> ctor = classObj.getDeclaredConstructor((Class[]) null);
    ctor.setAccessible(true);

    return (BaseClass) ctor.newInstance();
}

When running this method for a class that has a default constructor visibility (package private), i am getting a MissingMethod exception. Changing the constructor to public fixes the issue.

Answer 1

此方法返回在类中声明的构造函数，无论是否公开。但这并不意味着您可以使用返回的构造函数来实例化一个实例，这就是您收到错误的原因。如果不允许访问，则在此类构造函数上调用 setAccessible(true)。这与 getDeclaredMethod 和 getDeclaredFields 相同。