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1Z0-829 Java I/O API and Securing Applications Practice Question

Which resource declaration order in try-with-resources is valid when both a FileInputStream and a BufferedInputStream wrapping it need to be closed automatically?

⚠ Common exam trap

Oracle often tests the misconception that resources declared inside the try block (not in the resource list) are automatically closed, or that the order of declaration in try-with-resources does not matter for wrapping streams.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

try (FileInputStream fis = new FileInputStream("a"); BufferedInputStream bis = new BufferedInputStream(fis)) { ... }

In a try-with-resources statement, resources are declared in order and closed in reverse order. By declaring FileInputStream first and then BufferedInputStream wrapping it, both resources are properly closed automatically, with the BufferedInputStream closed first (ensuring its buffer is flushed) and then the FileInputStream.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
try (FileInputStream fis = new FileInputStream("a")) { BufferedInputStream bis = new BufferedInputStream(fis); ... }
Why it's wrong here
bis is not in the try header, so it is not automatically closed.
✓
try (FileInputStream fis = new FileInputStream("a"); BufferedInputStream bis = new BufferedInputStream(fis)) { ... }
Why this is correct
Both resources are declared in order; fis is closed after bis as resources are closed in reverse order.
✗
try (BufferedInputStream bis = new BufferedInputStream(fis); FileInputStream fis = new FileInputStream("a")) { ... }
Why it's wrong here
fis is used before declaration, causing a compilation error.
✗
try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream("a"))) { ... }
Why it's wrong here
Only one resource is declared, not both as required.

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1Z0-829 Java I/O API and Securing Applications Practice Question

Why each option matters

Option-by-option breakdown

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