Difference between static class and singleton pattern?

design-patterns static singleton
Jorge Córdoba picture Jorge Córdoba · Feb 6, 2009 · Viewed 514.2k times · Source

What real (i.e. practical) difference exists between a static class and a singleton pattern?

Both can be invoked without instantiation, both provide only one "Instance" and neither of them is thread-safe. Is there any other difference?

Answer

Jon Skeet picture Jon Skeet · Feb 6, 2009

What makes you say that either a singleton or a static method isn't thread-safe? Usually both should be implemented to be thread-safe.

The big difference between a singleton and a bunch of static methods is that singletons can implement interfaces (or derive from useful base classes, although that's less common, in my experience), so you can pass around the singleton as if it were "just another" implementation.

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