Which of the following is a reserved Java keyword (cannot be used as an identifier)?

Introduction / Context:
Java keywords are reserved by the language grammar. Using them as identifiers leads to compilation errors. This question targets recognition of true keywords versus ordinary words.

Given Data / Assumptions:

• A mix of non-keywords (everyday terms) and a real Java keyword is presented.

Concept / Approach:
native is a Java keyword used to mark methods implemented in non-Java code (typically via JNI). Words like method, subclasses, reference, and array are not reserved, even though they are common terminology.

Step-by-Step Solution:

Verification / Alternative check:
Try declaring variables with these names; only native will fail to compile as an identifier.

Why Other Options Are Wrong:
They are not part of Java’s reserved word list.

Common Pitfalls:
Confusing domain nouns with reserved language tokens.

Final Answer:
native