Mastering Java: The Ultimate Quiz for 'Thinking in Java'

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Mastering Java: The Ultimate Quiz for 'Thinking in Java'. Dive deep into Java with multiple-choice questions. Challenge yourself with quiz questions designed to test and improve your understanding of the 'Thinking in Java' book. Get ready for your exam!

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What exception is thrown if a downcast fails in Java?

NullPointerException
ClassCastException
RuntimeException
IllegalArgumentException

The correct answer is: ClassCastException

A downcast in Java is when an object is converted from a superclass type to a subclass type. The ClassCastException is thrown when an attempt to perform this conversion fails, indicating that the object is not an instance of the specified subclass. This is different from a NullPointerException, which is thrown when a null object is accessed, and from a RuntimeException, which is a general exception that is not specifically related to downcasting. Similarly, an IllegalArgumentException is thrown when an invalid argument is passed to a method, so it is not directly related to downcasting. Thus, the ClassCastException is the most appropriate exception to be thrown when a downcast fails in Java.