Exception Handling and Java I/O Flashcards

Which statement about checked exceptions is correct?

Answer: They must be caught or declared in the method signature using throws

Checked exceptions must either be handled with a try-catch or declared with the throws keyword in the method signature.

Which class should you use to efficiently write characters to a file using a buffer?

Answer: BufferedWriter

BufferedWriter wraps a Writer and uses an internal buffer to reduce I/O operations, improving performance.

What does the try-with-resources statement require of the resources it manages?

Answer: They must implement AutoCloseable

Resources used in try-with-resources must implement the AutoCloseable interface so close() can be called automatically.

Which exception is thrown when the JVM cannot find the definition of a class that is referenced at runtime?

Answer: NoClassDefFoundError

NoClassDefFoundError is thrown when a class was present at compile time but cannot be found at runtime.

What is the purpose of the ObjectOutputStream class?

Answer: To serialize Java objects to an output stream

ObjectOutputStream serializes Java objects (that implement Serializable) by writing them as a byte stream.

Which of the following exceptions is an unchecked exception?

Answer: NullPointerException

NullPointerException extends RuntimeException, making it unchecked; the compiler does not require it to be caught or declared.

When multiple exceptions are caught in a single catch block using multi-catch (Java 7+), which statement is true?

Answer: The caught exception variable is effectively final

In a multi-catch block, the exception parameter is implicitly final and cannot be reassigned.