1Z0-829 Flashcards — Free Oracle Certified Professional Java SE 17 Developer 1Z0-829 Study Cards

ZonedDateTime.now(zone).toOffsetDateTime()

Option B is correct because `ZonedDateTime.now(zone).toOffsetDateTime()` directly obtains the current date-time in the specified time zone and then converts it to an `OffsetDateTime` by extracting the zone offset. This approach correctly uses the provided `ZoneId` and returns the current time as an `OffsetDateTime` without any loss of precision or incorrect time manipulation.

It can be used with arrays and any object that implements Iterable.

The enhanced for loop (for-each) in Java can iterate over arrays and any object that implements the Iterable interface, which includes all Collection classes (e.g., List, Set, Queue). This is because the for-each loop internally uses an iterator for Iterable objects or array indexing for arrays, making it a versatile construct for traversing elements without needing an explicit counter.

World

Option B is correct because the Sub class overrides the print() method from Super and does not call super.print(). Therefore, when Sub's print() is executed, it only prints "World" without printing "Hello". The output is simply "World".

try (BufferedReader reader = Files.newBufferedReader(path)) { ... } catch (IOException e) { throw new ApplicationException(e); }

Option C is correct because it uses a try-with-resources statement, which automatically closes the BufferedReader (which implements AutoCloseable) when the block exits, whether normally or exceptionally. The catch clause then catches any IOException and wraps it in a custom ApplicationException, satisfying both the resource-closing and exception-wrapping requirements without manual cleanup.

Iterator<String> it = list.iterator(); while (it.hasNext()) { if (it.next().equals("x")) it.remove(); }

Option C is correct because the Iterator's remove() method is the only safe way to remove elements from a collection while iterating, as it updates both the iterator's internal cursor and the collection's modCount, preventing ConcurrentModificationException. The enhanced for-each loop (options A and D) uses an implicit iterator that does not expose a remove method, so calling list.remove() directly modifies the collection without updating the iterator's state, causing the exception. Option B avoids the exception by using an index-based loop, but it is unsafe because removing an element shifts subsequent elements left, causing the loop to skip the next element and potentially miss removals or throw an IndexOutOfBoundsException.

transactions.stream().filter(t -> t.type().equals("SALE") && t.currency().equals("USD")).mapToDouble(Transaction::amount).sum()

Option D correctly filters transactions to only those with type 'SALE' and currency 'USD', then maps each to its amount as a double, and sums them using sum(). This satisfies the requirement exactly: total amount of 'SALE' transactions in USD.

Maven Shade Plugin

The Maven Shade Plugin (B) is the correct choice because it creates an uber-JAR (fat JAR) by merging all project dependencies into a single executable JAR, including transitive dependencies. It also provides a relocation feature to avoid classpath conflicts, which is essential for producing a self-contained artifact for deployment.

Use a FileInputStream wrapped in a BufferedInputStream with a 8 KB buffer

Option A is correct because 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.