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Jon Skeet
Why Observable is still a class in Java 8?
Related Question:
Why is java.util.Observable not an abstract class?
Since we have interfaces which can contains default methods, isn't it a better idea to change Observable to an interface? From a functionality point of view, the Observable "does a thing" but not "is a thing". It should be changed to an interface in Java 8 correct?
It should be changed to an interface in Java 8 correct?
Not unless you want to break all backwards compatibility, no. If you changed it to an interface, then anything written as:
public class Foo extends Observable
would be broken. I suspect it may well also be invalid in terms of binary compatibility too, but just source incompatibility would be enough to make it a no-go change, IMO.
Likewise:
- It's currently a concrete class, not an abstract class... so
new Observable()is currently valid but wouldn't be as an interface - As you say yourself in another answer, the default implementation uses state... so it can't be implemented by interface default methods
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