Does Java allow to create static classes

Question

If it is possible - what is the meaning of such a class. Do all the methods of the static class need to be static too?

Is it required the other way round, that if a class contains all the static methods, shall the class be static too?

What are static classes good for?

Answer 1

n votceJava has static nested classes but you need a top-level static class. Java has no way of making a top-level class static but you can simulate a static class like this:

• Declare your class final - Prevents extension of the class since extending a static class makes no sense
• Make all the members and functions of the class static - Since the class cannot be instantiated no instance methods can be called or instance fields accessed
• Make the constructor private - Prevents instantiation by client code as it makes no sense to instantiate a static class

Note that the compiler will not prevent you from declaring an instance (non-static) member. The issue will only show up if you attempt to call the instance member

down voteaccepted

Answer 2

Java has "static nested classes", but they are not at all the same as C#'s static classes, if that's where you were coming from.

A static nested class is just one which doesn't implicitly have a reference to an instance of the outer class.

Static nested classes can have instance methods and static methods.

There's no such thing as a top-level static class in Java.