C# sealed vs Java final
That's because final
in Java means plenty of different things depending on where you use it whereas sealed
in C# applies only to classes and inherited virtual members (methods, properties, events).
In Java final
can be applied to:
- classes, which means that the class cannot be inherited. This is the equivalent of C#'s
sealed
. - methods, which means that the method cannot be overridden in a derived class. This is the default in C#, unless you declare a method as
virtual
and in a derived class this can be prevented for further derived classes withsealed
again. That's why you seesealed
members in C# a lot less thanfinal
members in Java. - fields and variables, which means that they can only be initialized once. For fields the equivalent in C# is
readonly
.
Sealed
in C#
can be applied only to a reference types, and has impact on inheritance tree.
In practise the type marked as sealed
guranteed to be the last "leaf" in the inheritance tree, or in short, you can not derive from the type declared like a sealed
.
public sealed class Child : Base
{
}
public class AnotherAgain : Child //THIS IS NOT ALLOWED
{
}
It can not be applied to a members.
Tigran's answer is not wrong while Joey's is a little incorrect.
Firstly you can look into this page: What is the equivalent of Java's final in C#?.
the sealed
key word can apply to class
,instance method
and property
but not variables, or interface's methods. Classes with sealed
cannot be inherited. When sealed
put on method, it must be by override
in company. Every struct
is sealed
, so struct
cannot be inherited. Check this image: