private-constructor

This question already has an answer here: Java — private constructor vs final and more 3 answers As per my understanding Final class A final class is simply a class that can't be extended. A class with single no argument private constructor A class with private constructors cannot be instantiated except form inside that same class. This make it useless to extend it from another class. But it does not mean it cannot be sub classed at all, among inner classes we can extend and call the private constructor. So my understanding is, if we create a class with single no argument private constructor,

I searched for this a lot, but none of the answers are clear (at-least for me!). Now I'm putting this question in SO, as I believe I can't get a more clarified answer anywhere else. When should I use a private/static constructor in my class? I'm fed up of usual answers, so please help me with some real-time examples and advantages/disadvantages of using these constructors. Static constructors: used for initialising static members. Private constructors: used when you only want a class to be instantiated from within its own code (typically in a static method). For example: public class Thing {

In reading TCPL , I got a problem, as the title refered, and then 'private' class is: class Unique_handle { private: Unique_handle& operator=(const Unique_handle &rhs); Unique_handle(const Unique_handle &rhs); public: //... }; the using code is: struct Y { //... Unique_handle obj; }; and I want to execute such operations: int main() { Y y1; Y y2 = y1; } although, these code are come from TCPL, but I still can not got the solution... Can anybody help me, appreciate. As its name suggests, the Unique_handle isn't meant to be copied. Its implementation ensures it by disabling the copy constructor

A common thing to do to utility classes is to give them a private constructor : public final class UtilClass { private UtilClass() {} ... } But unfortunately, some tools don't like that private constructor. They may warn that it's never called within the class, that it's not covered by tests, that the block doesn't contain a comment, etc. A lot of those warnings go away if you do this instead: public enum UtilClass {; ... } My question is: besides the unending hatred of future developers, what important differences are there between an enum with no values and a class with a private constructor