The correct answer is that `Files.lines()` with try-with-resources allows streaming of lines, while `Files.newBufferedReader()` returns a buffered character stream for efficient line-by-line reading. `Files.lines()` is a lazy, stream-based method that reads lines on-demand, making it ideal for large files because it does not load the entire file into memory, but it must be used within a try-with-resources block to ensure the underlying file channel is closed. `Files.newBufferedReader()`, by contrast, wraps a `FileChannel` in a `BufferedReader` for high-performance sequential reading, suitable for iterative processing without stream overhead. On the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, this comparison tests your understanding of resource management and memory efficiency in NIO.2 file reading methods. A common trap is forgetting that `Files.readAllLines()` loads the entire file into a `List`, which can cause `OutOfMemoryError` for large files, whereas `Files.lines()` and `newBufferedReader()` avoid this. Memory tip: “Stream lines, don’t collect them all” — use `lines()` for large files, `readAllLines()` only for small ones.
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. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which TWO statements are true regarding reading files with the NIO.2 API?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Files.newBufferedReader() provides buffered character input.
Option B is correct because `Files.newBufferedReader()` returns a `BufferedReader` that wraps a `FileReader` (or underlying `FileChannel`), providing efficient buffered character input. This method is designed for reading text files line-by-line with reduced I/O operations, making it suitable for large or stream-oriented text processing.
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.
✗
Files.readAllLines() is memory efficient for large files.
Why it's wrong here
readAllLines loads all lines into memory, which is not efficient.
✓
Files.newBufferedReader() provides buffered character input.
Why this is correct
newBufferedReader returns a BufferedReader for efficient reading.
Related concept
Read the scenario before looking for a memorised answer.
✓
Files.lines() with try-with-resources allows streaming of lines.
Why this is correct
lines() returns a Stream that processes lines lazily.
Related concept
Read the scenario before looking for a memorised answer.
✗
Files.newInputStream() wraps a FileChannel for high performance.
Why it's wrong here
newInputStream returns an InputStream, not a FileChannel; not necessarily high performance.
✗
Files.readAllBytes() is the best choice for large binary files.
Why it's wrong here
readAllBytes loads entire file into memory, not suitable for large files.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Oracle often tests the distinction between memory-hungry convenience methods (`readAllLines`, `readAllBytes`) and streaming approaches (`lines`, `newBufferedReader`), trapping candidates who assume 'readAll' methods are efficient for large files.
Detailed technical explanation
How to think about this question
Under the hood, `Files.lines()` uses a `BufferedReader` internally and returns a `Stream<String>` that lazily reads lines, allowing processing of files larger than memory when combined with try-with-resources to ensure the underlying file channel is closed. In contrast, `Files.readAllLines()` and `Files.readAllBytes()` are convenience methods that sacrifice memory efficiency for simplicity, making them suitable only for small files. The NIO.2 API also supports `SeekableByteChannel` for random access, but `Files.newBufferedReader()` and `Files.lines()` are optimized for sequential text processing.
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 practitioner preparing for the 1Z0-829 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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: Files.newBufferedReader() provides buffered character input. — Option B is correct because `Files.newBufferedReader()` returns a `BufferedReader` that wraps a `FileReader` (or underlying `FileChannel`), providing efficient buffered character input. This method is designed for reading text files line-by-line with reduced I/O operations, making it suitable for large or stream-oriented text processing.
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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Question Discussion
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