Java basics
1. Only three members can appear in the interface.
1. Public static constant (public final static)
2. Public abstract method (public abstract )
3. Static inner class (static class)
In a class, even if you don't write anything, you must also take a constructor. In the extends, it will be inherited by the subclass. If the interface inherits the constructor, it is obviously constructed. Method is not in the above three items
and if there are general methods and member variables in the class, they will all be inherited by the subclass. These can't appear in the interface, so
It is absolutely impossible to inherit a class from an interface.
2. The interface cannot implement the interface.
Third, the interface is the implementation of the interface, not the method of the parent interface.
The abstract class implements the interface, and can also implement the method of the parent interface. Nothing is written, which also explains the method of the interface inheritance interface is not written.
Five. Abstract classes cannot be instantiated
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