If a method is defined as final then we can’t provide the reimplementation for that final method in it’s derived classes i.e overriding is not possible for that method.
An abstract class contains one or mole abstract method. If all the methods ar of type abstract then use we can declare that class as abstract or interface. But in interface all the methods must be of type abstract.
We can declare final method in abstract class suppose of it is abstract too, then there is no used to declare like that.
Final abstract int test(String str);
Here we can’t provide the implementation for the test method as it is declared as final. But at the same time you declare it as abstract. [Abstract means it is responsibility of derived class to provide implementation for this] Here we can’t provide the implementation for the test method. Even we descried to provide implementation totally our meaning for declaring it as abstract is spoiled.