Core Java preguntas y respuestas de entrevista
Question: What does the "final" keyword mean in front of a variable? A method? A class?Answer: FINAL for a variable : value is constantFINAL for a method : cannot be overridden FINAL for a class : cannot be derived A final variable cannot be reassigned, but it is not constant. For instance, final StringBuffer x = new StringBuffer() x.append("hello"); is valid. X cannot have a new value in it,but nothing stops operations on the object that it refers, including destructive operations. Also, a final method cannot be overridden or hidden by new access specifications.This means that the compiler can choose to in-line the invocation of such a method.(I don't know if any compiler actually does this, but it's true in theory.) The best example of a final class is String, which defines a class that cannot be derived. |
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