C# sealed vs Java final

Question

Would anybody please tell me as the reason the following use of sealed does not compile? Whereas, if I replace sealed with final and compile it as Java, it works.

private sealed int compInt = 100;
public bool check(int someInt)
{
    if (someInt > compInt)
    {
        return true;
    }
    return false;
}

Answer 1

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 with sealed again. That's why you see sealed members in C# a lot less than final members in Java.
• fields and variables, which means that they can only be initialized once. For fields the equivalent in C# is readonly.