Question 186 of 513
1Z0-829 Java I/O API and Securing Applications Practice Question
A developer is tasked with reading a large binary file (1 GB) from a network share using the least amount of memory possible. Which approach should be used?
⚠ Common exam trap
Watch out — candidates often confuse 'least memory' with 'fastest performance' and choose Files.readAllBytes() for simplicity, or they incorrectly assume RandomAccessFile is more memory-efficient, when in fact buffered streaming is the standard low-memory approach for large binary files.
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
✓
Use a FileInputStream wrapped in a BufferedInputStream with a 8 KB buffer
Using a FileInputStream wrapped in a BufferedInputStream with a small buffer (e.g., 8 KB) allows reading the file in chunks without loading the entire 1 GB into memory. This approach minimizes heap usage by processing data incrementally, which is essential for large binary files over a network share where memory constraints are critical.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use a FileInputStream wrapped in a BufferedInputStream with a 8 KB buffer
Why this is correct
This reads the file in chunks with a small buffer, minimizing memory footprint.
- ✗
Read the entire file into a byte array using Files.readAllBytes()
Why it's wrong here
This loads the entire file into memory, which is not memory-efficient for large files.
- ✗
Use a FileReader wrapped in a BufferedReader to read lines
Why it's wrong here
FileReader is for character data, not binary files, and still holds data in memory.
- ✗
Use a RandomAccessFile to read the file in segments
Why it's wrong here
RandomAccessFile requires a file descriptor for the entire resource, which causes significant overhead when accessing large files over network protocols. This approach is intended for non-sequential data manipulation where you must jump to specific offsets within the byte stream. It would be correct if the task required frequent seeks and updates to various parts of the binary data rather than a single sequential read.
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Last reviewed: Jun 11, 2026
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