In Java programming, which of the following statements about the use of assertions is correct according to standard Java guidelines?

Introduction / Context:
Assertions in Java are a development-time tool used to check assumptions made by the programmer. They can be enabled or disabled at run time using the JVM command-line options. Because assertions may be turned off in production, they are not suitable for enforcing conditions that must always be checked, especially for external input. This question tests knowledge of recommended practices for when assertions should and should not be used.

Given Data / Assumptions:

• Assertions can be disabled at run time using the JVM flags -ea or -da.
• Public methods and command-line arguments represent external contracts and inputs.
• Java guidelines distinguish between checking internal invariants and validating external data.
• The question asks which statement about the proper use of assertions is correct.

Concept / Approach:
Java best practices recommend using assertions to test internal assumptions in code that should hold if there are no bugs, particularly in private methods or internal logic branches. They should not be used for argument checking in public methods or for validating command-line arguments, configuration files, or user input, because these checks must remain active regardless of whether assertions are enabled. External input should be validated with explicit error handling, usually by throwing checked or unchecked exceptions.

Step-by-Step Solution:
Step 1: Consider public methods. Their arguments come from external callers, and input checking is part of the method contract. Assertions, which may be disabled, are not appropriate here.Step 2: Consider command-line arguments. They are external data supplied by the user or environment, and must always be validated to prevent errors or security issues.Step 3: Recognize that AssertionError is intended to indicate programmer mistakes, not normal recoverable conditions, so catching and handling it in application logic is discouraged.Step 4: Among the options, the statement that clearly aligns with this guidance is that it is not appropriate to use assertions to validate command-line arguments or other external inputs.Step 5: Therefore, option C is the correct description.

Verification / Alternative check:
The official Java language specification and standard coding guidelines state that assertions are meant to test internal invariants and that they should not be used for argument checking in public methods or for validating external input. They also note that AssertionError is usually not caught, because it represents an unexpected violation of a programmer assumption rather than a normal error condition.

Why Other Options Are Wrong:
Option A is incorrect because public method arguments must be validated even when assertions are disabled; therefore, explicit checks with exceptions are preferred. Option B is wrong because catching AssertionError and treating it as a normal error defeats the purpose of assertions and can hide programming bugs. Option D is incorrect because option C accurately reflects recommended practice.

Common Pitfalls:
Developers sometimes overuse assertions for all kinds of checks, including user input validation and parameter checking in public APIs. This can lead to situations where critical validation disappears when assertions are turned off in production. Another pitfall is relying on assertions for security checks; they are not a substitute for proper validation and error handling.

Final Answer:
The correct statement is that it is NOT appropriate to use assertions to validate command-line arguments or other external inputs.