The correct answer is to switch to using try-with-resources for all FileOutputStream instances and wrap them in BufferedOutputStream with a larger buffer. This resolves the java.io.IOException because try-with-resources guarantees automatic closure of the stream, preventing the resource leak that causes file locking conflicts on Windows when multiple threads write to separate files in the same directory. On the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, this scenario tests your understanding of resource management under the try-with-resources statement (introduced in Java 7 and enhanced in Java 9 with effectively-final variables) and the performance benefits of buffered I/O. A common trap is assuming that closing a stream in a finally block is sufficient—but unhandled exceptions can skip that block, whereas try-with-resources is exception-safe by design. For the performance slowdown under heavy network load, wrapping the stream in BufferedOutputStream with a larger buffer reduces the number of physical write operations, batching data to minimize latency. Memory tip: think "TRY it, then RESOURCE it away" — if you open it, try-with-resources will close it.
1Z0-829 Java I/O API and Securing Applications Practice Question
This 1Z0-829 practice question tests your understanding of java i/o api and securing applications. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A financial trading application processes real-time stock data from multiple exchanges. The application reads large binary files (each up to 500 MB) containing trade records, processes them, and writes summary reports to a shared network drive. The development team observes that the application occasionally throws a java.io.IOException: 'The process cannot access the file because it is being used by another process' when writing reports. The application is multi-threaded, and each thread writes to a separate file in the same directory. The team also notices that the application slows down significantly when the network drive is under heavy load. The application runs on Windows servers with Java 17. The code uses FileOutputStream for writing and does not explicitly close streams in some paths. Which course of action should the team take to resolve the issues and improve performance?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Switch to using try-with-resources for all FileOutputStream instances and wrap them in BufferedOutputStream with a larger buffer.
Option C is correct because the primary issue is resource leaks from not closing FileOutputStream instances, which can cause file locking conflicts on Windows when multiple threads write to separate files in the same directory. Using try-with-resources ensures streams are closed reliably, eliminating the 'file in use' IOException. Wrapping with BufferedOutputStream and a larger buffer reduces the number of write operations to the network drive, mitigating slowdowns under heavy load by batching data and minimizing latency.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Increase the thread pool size to handle more concurrent writes.
Why it's wrong here
More threads may increase contention and locking issues.
✗
Use FileChannel with FileLock to synchronize access.
Why it's wrong here
FileLock is for cross-process locking, not needed here, and can cause contention.
✓
Switch to using try-with-resources for all FileOutputStream instances and wrap them in BufferedOutputStream with a larger buffer.
Why this is correct
This ensures proper closure and reduces I/O calls, mitigating both issues.
Related concept
Read the scenario before looking for a memorised answer.
✗
Write to local temporary files and then copy to the network drive.
Why it's wrong here
While this may reduce network contention, it does not address the stream closure issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think file locking (Option B) is needed for multi-threaded file access, but the question specifies each thread writes to a separate file, making locking irrelevant, while the real issue is resource leaks from unclosed streams and performance from unbuffered writes.
Detailed technical explanation
How to think about this question
Under the hood, FileOutputStream acquires a file handle from the operating system; on Windows, if the stream is not closed, the handle remains open, preventing other processes (or even the same JVM) from accessing the file with write access. BufferedOutputStream wraps the underlying stream with an internal buffer (default 8192 bytes), and a larger buffer (e.g., 64 KB or 128 KB) reduces the number of system calls to the network drive, which is critical because each write call incurs network round-trip latency. The try-with-resources construct automatically calls close() in a finally block, ensuring the file handle is released even if an exception occurs, which is a best practice in Java I/O.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Java I/O API and Securing Applications — This question tests Java I/O API and Securing Applications — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Switch to using try-with-resources for all FileOutputStream instances and wrap them in BufferedOutputStream with a larger buffer. — Option C is correct because the primary issue is resource leaks from not closing FileOutputStream instances, which can cause file locking conflicts on Windows when multiple threads write to separate files in the same directory. Using try-with-resources ensures streams are closed reliably, eliminating the 'file in use' IOException. Wrapping with BufferedOutputStream and a larger buffer reduces the number of write operations to the network drive, mitigating slowdowns under heavy load by batching data and minimizing latency.
What should I do if I get this 1Z0-829 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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