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

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Dive into the depths of Java with our quiz based on "Thinking in Java, Fourth Edition" by Bruce Eckel. Test your knowledge, solidify concepts, and prepare for certification with challenging questions and insightful feedback.

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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Which concept allows a class in Java to be 'upcast' to more than one base type?

Polymorphism
Interfaces
Multiple Inheritance
Composition

The correct answer is: Interfaces

Interfaces in Java allow a class to inherit or extend from more than one base type. Unlike multiple inheritance where a class inherits properties and methods from multiple classes, interfaces only define methods and the class needs to provide an implementation for these methods. Polymorphism refers to the ability of objects to take on different forms and is not directly related to the concept of 'upcasting'. Multiple inheritance is not allowed in Java as it can lead to conflicts and confusion. Composition refers to the ability of a class to contain objects of other classes, but it does not allow the class to inherit from multiple base types. Therefore, B is the correct choice.