In Java exception handling, what is the key difference between the throw statement and the throws clause in a method declaration?

Introduction / Context:
Java exception handling uses a combination of try, catch, finally, throw, and throws to manage error conditions. Because throw and throws look similar, many beginners confuse their roles. Understanding the difference is critical for designing clean APIs and for working with checked exceptions. This question explores how throw and throws are used differently in Java code.

Given Data / Assumptions:

• Java supports both checked and unchecked exceptions.
• Methods can signal error conditions either by throwing exceptions or by declaring that they may throw them.
• The compiler enforces handling or declaration of checked exceptions.
• throw and throws are distinct language constructs even though they share a root word.

Concept / Approach:
The throw statement is used inside method bodies to actually create or rethrow an exception object at runtime. For example, throw new IllegalArgumentException creates an instance and transfers control to the nearest matching catch block or out of the method. The throws clause appears in the method signature, after the parameter list, and lists the types of exceptions that the method may allow to escape. This clause does not throw anything by itself; it simply informs callers and the compiler about possible exceptions they must handle or propagate further. Together, throw and throws support precise control over error signalling and handling.

Step-by-Step Solution:
Step 1: Focus on throw, which is a statement inside a method body that takes a single exception object reference as its operand.Step 2: When the throw statement executes, normal flow stops and the runtime searches for an appropriate catch block in the current or calling methods.Step 3: Now consider throws, which appears in the method declaration and lists exception classes, for example public void readFile() throws IOException.Step 4: The throws clause communicates that the method might throw these exceptions, either directly or indirectly, and that callers must handle or declare them.Step 5: Conclude that throw causes the actual exception event, while throws is a declaration of potential exceptions in the API.

Verification / Alternative check:
Examining Java syntax clarifies that throw is followed by an expression and ends with a semicolon, just like any other statement. In contrast, throws is part of the method header and is followed by a comma separated list of exception types. Compilers require throws for checked exceptions that are not handled inside the method. If you remove a throws clause but still call a method that throws a checked exception, you will see compile time errors, confirming the declarative role of throws.

Why Other Options Are Wrong:
Option B incorrectly divides throw and throws by checked versus unchecked exceptions; both constructs can be used with either kind. Option C suggests that throw clears exceptions and throws logs them, which has no basis in the language specification. Option D states that there is no difference and that the keywords are interchangeable, which is clearly false because their syntax positions and meanings are distinct. Only option A correctly describes the runtime action versus the signature declaration roles.

Common Pitfalls:
A common pitfall is forgetting to declare a checked exception in a throws clause when rethrowing it, which leads to compile time errors. Another mistake is overusing throws to bubble every exception up without considering whether to handle some cases locally. Good design carefully chooses which exceptions to throw, wraps low level exceptions with more meaningful ones, and declares throws clauses that accurately reflect what callers must be aware of. Understanding the separation between throw and throws is a foundation for these design decisions.

Final Answer:
Correct answer: throw actually creates and throws a specific exception object at runtime, whereas throws declares in the method signature which exceptions may be propagated to the caller