Mastering Java: The Ultimate Quiz for 'Thinking in Java' 2026 - Free Java Programming Practice Questions and Study Guide

Upcasting refers to the process of casting an object to a more general, or superclass, type. This allows the object to inherit the properties and methods of the superclass, but it may also have additional properties and methods specific to its original class. Option A is incorrect because casting an object to a more specific class is known as 'downcasting'. Option C is incorrect because it does not involve changing the type of the object at all. Option D is incorrect because casting an object to a sibling class is not possible in polymorphism, as sibling classes have different parent classes.