1Z0-829 Practice Test 6 — 10 Questions

Question 1

A reporting module formats durations for a dashboard. The developer writes:

Duration d = Duration.ofMinutes(90);
System.out.println(d.toMinutes() + ":" + d.toMinutesPart());

What is printed?

Accepted Answer

90:30. Duration exposes both total-unit accessors and component accessors. toMinutes() returns the entire duration expressed in whole minutes, giving 90 for a 90-minute duration, while toMinutesPart() returns only the minutes left after whole hours are removed, giving 30. Concatenating them yields 90:30.

Answer

90:90

Answer

1:30

Answer

A DateTimeException is thrown because Duration has no hour component.

Question 2

What is the output of the following code?

```java
int i = 5;
while (i > 0) {
    System.out.print(i + " ");
    i--;
}
```

Accepted Answer

5 4 3 2 1. The while loop runs as long as i > 0. Starting with i = 5, each iteration prints the current value of i followed by a space, then decrements i by 1. The loop stops when i becomes 0, so the output is '5 4 3 2 1 '.

Answer

The code does not compile because i is not declared final.

Answer

5 4 3 2

Answer

4 3 2 1

Question 3

Given a list of strings, which of the following will produce a Map<String, Long> counting the occurrences of each string?

Accepted Answer

.collect(Collectors.groupingBy(Function.identity(), Collectors.counting())). `Collectors.groupingBy(Function.identity(), Collectors.counting())` groups each string by itself (using `Function.identity()` as the classifier) and then applies a downstream collector `Collectors.counting()` that counts the number of elements in each group, producing a `Map<String, Long>` where each key is a unique string and the value is its frequency.

Answer

.collect(Collectors.toMap(Function.identity(), String::length))

Answer

.collect(Collectors.groupingBy(Function.identity(), Collectors.summingInt(e->1)))

Answer

.collect(Collectors.toMap(Function.identity(), v->1))

Question 4

Which TWO are terminal operations on the Stream interface? (Choose two.)

Accepted Answer

count(). Option A, count(), is a terminal operation because it triggers the stream pipeline to execute and returns a long result (the number of elements), consuming the stream so it cannot be reused. Option B, forEach(), is also terminal: it accepts a Consumer and performs an action on each element, causing the pipeline to run and rendering the stream consumed. By contrast, filter(), map(), and sorted() are intermediate operations—they return a new Stream (or a specialized stream) and are lazy, merely building up the pipeline until a terminal operation is invoked. Therefore C, D, and E do not belong among the terminal operations.

Answer

filter()

Answer

map()

Answer

sorted()

Question 5

A Java application running on a server reads configuration from a file 'config.properties' located in the same directory as the JAR. The application uses java.util.Properties.load(InputStream) to read the file. Recently, the file was modified by an unauthorized user, and the application started throwing runtime exceptions due to corrupted property values. The security team requires that the file be protected from unauthorized modifications while still being readable by the application. Which action should be taken to ensure the integrity of the configuration file?

Accepted Answer

Digitally sign the file and verify the signature before loading properties.. Digital signing provides both integrity and authenticity. By signing the file with a private key and verifying the signature with a public key before calling Properties.load(InputStream), the application can detect any unauthorized modification. This directly addresses the security requirement without relying on encryption (which protects confidentiality, not integrity) or file permissions (which can be bypassed by a privileged attacker).

Answer

Encrypt the file using AES and decrypt it in the application.

Answer

Set the file permissions to read-only for the application user.

Answer

Store the file in a ZIP archive with a checksum.

Question 6

A resource is declared in a try-with-resources statement. The try block throws an exception. The close method throws a different exception. What exception is thrown by the try-with-resources statement?

Accepted Answer

The exception from the try block.. In a try-with-resources statement, if both the try block and the close() method throw exceptions, the exception from the try block is the one thrown by the statement. The exception from close() is suppressed and added to the thrown exception's suppressed exception list (via Throwable.addSuppressed()). This is specified by JLS §14.20.3.2 and ensures the primary failure (the try block exception) is not masked.

Answer

The exception from the close method.

Answer

A compilation error occurs.

Answer

Both exceptions are thrown simultaneously.

Question 7

A development team wants to ensure that a Java 17 application runs with a specific set of modules. They want to minimize the footprint by including only necessary modules. Which tool should they use?

Accepted Answer

jlink. B is correct because jlink is the Java tool specifically designed to assemble and optimize a custom runtime image containing only the modules explicitly required by an application. It analyzes module dependencies and produces a minimal JRE, reducing footprint by excluding unused modules, which aligns with the team's goal of minimizing size.

Answer

javac

Answer

jmod

Answer

jar

Question 8

Which THREE statements about the jpackage tool are true?

Accepted Answer

jpackage can create native installers for Windows, macOS, and Linux.. The jpackage tool is designed to create native installers for Windows (e.g., .exe/.msi), macOS (e.g., .dmg), and Linux (e.g., .deb/.rpm). This is a core feature of jpackage, which replaces the older Java Packager and allows developers to distribute self-contained applications with platform-specific packaging formats.

Answer

jpackage requires an existing JRE to create a runtime image.

Answer

jpackage uses the Java Packager library.

Question 9

What is the output when this code is executed?

```java
int x = 2;
switch (x) {
    case 1:
        System.out.print("One ");
    case 2:
        System.out.print("Two ");
    case 3:
        System.out.print("Three ");
        break;
    default:
        System.out.print("Default");
}
```

Accepted Answer

Two Three. The switch statement matches the value 2, so it executes the case 'Two' block, which prints 'Two ' and then falls through to the next case because there is no break statement. The case 'Three' block prints 'Three ' and then breaks, exiting the switch. The default case is skipped because a matching case was found and the break in case 'Three' prevents further fall-through. Thus, the output is 'Two Three '.

Answer

Two

Answer

Two Three Default

Answer

One Two Three

Question 10

Refer to the exhibit. What is the output?

```java
import java.util.stream.IntStream;

public class Example {
    public static void main(String[] args) {
        int sum = IntStream.rangeClosed(0, 5)
                .filter(i -> i >= 0)
                .sum();
        System.out.println(sum);
    }
}
```

Accepted Answer

15. The stream pipeline starts with `IntStream.rangeClosed(0, 5)` producing the integers 0, 1, 2, 3, 4, 5. The filter passes all these values, and the map is an identity function (or absent). The reduction sums them: 0+1+2+3+4+5 = 15. Therefore, the output is 15.

Answer

0

Answer

10

Answer

5