Oracle Java SE 21 Developer Professional - 1z0-830 Free Exam Questions

QUESTION NO: 1
Given:
java
List<Long> cannesFestivalfeatureFilms = LongStream.range(1, 1945)
.boxed()
.toList();
try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
cannesFestivalfeatureFilms.stream()
.limit(25)
.forEach(film -> executor.submit(() -> {
System.out.println(film);
}));
}
What is printed?

Correct Answer: D Vote an answer
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QUESTION NO: 2
Given:
java
interface SmartPhone {
boolean ring();
}
class Iphone15 implements SmartPhone {
boolean isRinging;
boolean ring() {
isRinging = !isRinging;
return isRinging;
}
}
Choose the right statement.

Correct Answer: A Vote an answer
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QUESTION NO: 3
Which three of the following are correct about the Java module system?

Correct Answer: B,C,F Vote an answer
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QUESTION NO: 4
Given:
java
DoubleSummaryStatistics stats1 = new DoubleSummaryStatistics();
stats1.accept(4.5);
stats1.accept(6.0);
DoubleSummaryStatistics stats2 = new DoubleSummaryStatistics();
stats2.accept(3.0);
stats2.accept(8.5);
stats1.combine(stats2);
System.out.println("Sum: " + stats1.getSum() + ", Max: " + stats1.getMax() + ", Avg: " + stats1.getAverage()); What is printed?

Correct Answer: C Vote an answer
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QUESTION NO: 5
Which of the following statements oflocal variables declared with varareinvalid?(Choose 4)

Correct Answer: B,D,E,F Vote an answer
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QUESTION NO: 6
Given:
java
Integer frenchRevolution = 1789;
Object o1 = new String("1789");
Object o2 = frenchRevolution;
frenchRevolution = null;
Object o3 = o2.toString();
System.out.println(o1.equals(o3));
What is printed?

Correct Answer: E Vote an answer
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QUESTION NO: 7
Which of the following java.io.Console methods doesnotexist?

Correct Answer: A Vote an answer
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QUESTION NO: 8
What does the following code print?
java
import java.util.stream.Stream;
public class StreamReduce {
public static void main(String[] args) {
Stream<String> stream = Stream.of("J", "a", "v", "a");
System.out.print(stream.reduce(String::concat));
}
}

Correct Answer: B Vote an answer
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QUESTION NO: 9
How would you create a ConcurrentHashMap configured to allow a maximum of 10 concurrent writer threads and an initial capacity of 42?
Which of the following options meets this requirement?

Correct Answer: E Vote an answer
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