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

How does Java ensure you cannot put an incorrect type into a type-specific array?

1. Using runtime type identification

2. Through compile-time and runtime checks

3. By erasing the type in runtime

4. Java does not provide such a mechanism

The correct answer is: Through compile-time and runtime checks

Java ensures that you cannot put an incorrect type into a type-specific array through both compile-time and runtime checks. This means that Java will flag any code that attempts to assign a value of the wrong type to an array element during both the compilation and execution phases. This helps to prevent errors and maintain type safety within the program. The other options are incorrect because A) Runtime type identification refers to the ability for a program to determine the type of an object at runtime, not to prevent incorrect type assignments. C) Erasing the type in runtime is a feature of certain languages, but it is not a mechanism used by Java to prevent incorrect type assignments. D) Java does provide a mechanism to ensure type safety in arrays.