1Z0-819 I/O Operations 3

Question 1

Which `Files` method reads all lines of a text file into a `List<String>` using the default charset?

Accepted Answer

Files.readAllLines(path)

Answer

`Files.readAllLines(path)` reads all lines into a `List<String>` using UTF-8 by default in Java 11.

Question 2

What is the key difference between `Files.lines(path)` and `Files.readAllLines(path)`?

Accepted Answer

`Files.lines` returns a lazy `Stream<String>` while `readAllLines` loads everything into memory immediately

Answer

`Files.lines` is lazy and streams lines on demand, whereas `readAllLines` materializes all lines into a `List` at once.

Question 3

Which method creates all missing parent directories for a given path in one call?

Accepted Answer

Files.createDirectories(path)

Answer

`Files.createDirectories` creates the target directory and all missing parents without throwing an error if they already exist.

Question 4

What does `Path.normalize()` do?

Accepted Answer

Removes redundant `.` and `..` elements from the path

Answer

`normalize()` eliminates redundant `.` (current directory) and `..` (parent directory) segments without accessing the filesystem.

Question 5

Which method on `Path` combines the current path with another path segment?

Accepted Answer

resolve()

Answer

`resolve()` appends the given path to the base path, handling absolute/relative combinations correctly.

(1Z0-819) Oracle Java SE 11 Developer Practice Test