1z1-830無料問題集「Oracle Java SE 21 Developer Professional」

質問 1

A module com.eiffeltower.shop with the related sources in the src directory.
That module requires com.eiffeltower.membership, available in a JAR located in the lib directory.
What is the command to compile the module com.eiffeltower.shop?

（A）css
CopyEdit
javac -path src -p lib/com.eiffel.membership.jar -d out -m com.eiffeltower.shop

（B）bash
CopyEdit
javac -source src -p lib/com.eiffel.membership.jar -d out -m com.eiffeltower.shop

（C）css
CopyEdit
javac --module-source-path src -p lib/com.eiffel.membership.jar -s out -m com.eiffeltower.shop

（D）css
CopyEdit
javac --module-source-path src -p lib/com.eiffel.membership.jar -d out -m com.eiffeltower.shop

正解：D 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 2

What do the following print?
java
public class DefaultAndStaticMethods {
public static void main(String[] args) {
WithStaticMethod.print();
}
}
interface WithDefaultMethod {
default void print() {
System.out.print("default");
}
}
interface WithStaticMethod extends WithDefaultMethod {
static void print() {
System.out.print("static");
}
}

（A）Compilation fails

（B）static

（C）nothing

（D）default

正解：B 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 3

Which of the following statements oflocal variables declared with varareinvalid?(Choose 4)

（A）var d[] = new int[4];

（B）var e;

（C）var f = { 6 };

（D）var b = 2, c = 3.0;

（E）var h = (g = 7);

（F）var a = 1;(Valid: var correctly infers int)

正解：A、B、C、D 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 4

Given:
java
var sList = new CopyOnWriteArrayList<Customer>();
Which of the following statements is correct?

（A）The CopyOnWriteArrayList class's iterator reflects all additions, removals, or changes to the list since the iterator was created.

（B）The CopyOnWriteArrayList class is not thread-safe and does not prevent interference amongconcurrent threads.

（C）The CopyOnWriteArrayList class is a thread-safe variant of ArrayList where all mutative operations are implemented by making a fresh copy of the underlying array.

（D）The CopyOnWriteArrayList class does not allow null elements.

（E）Element-changing operations on iterators of CopyOnWriteArrayList, such as remove, set, and add, are supported and do not throw UnsupportedOperationException.

正解：C 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 5

Given:
var cabarets = new TreeMap<>();
cabarets.put(1, "Moulin Rouge");
cabarets.put(2, "Crazy Horse");
cabarets.put(3, "Paradis Latin");
cabarets.put(4, "Le Lido");
cabarets.put(5, "Folies Bergere");
System.out.println(cabarets.subMap(2, true, 5, false));
What is printed?

（A）{}

（B）Compilation fails.

（C）{2=Crazy Horse, 3=Paradis Latin, 4=Le Lido}

（D）CopyEdit{2=Crazy Horse, 3=Paradis Latin, 4=Le Lido, 5=Folies Bergere}

（E）An exception is thrown at runtime.

正解：C 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 6

Given:
java
var ceo = new HashMap<>();
ceo.put("Sundar Pichai", "Google");
ceo.put("Tim Cook", "Apple");
ceo.put("Mark Zuckerberg", "Meta");
ceo.put("Andy Jassy", "Amazon");
Does the code compile?

（A）False

（B）True

正解：A 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 7

What do the following print?
java
public class Main {
int instanceVar = staticVar;
static int staticVar = 666;
public static void main(String args[]) {
System.out.printf("%d %d", new Main().instanceVar, staticVar);
}
static {
staticVar = 42;
}
}

（A）666 42

（B）Compilation fails

（C）666 666

（D）42 42

正解：D 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 8

Given:
java
public static void main(String[] args) {
try {
throw new IOException();
} catch (IOException e) {
throw new RuntimeException();
} finally {
throw new ArithmeticException();
}
}
What is the output?

（A）ArithmeticException

（B）RuntimeException

（C）Compilation fails

（D）IOException

正解：A 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

1z1-830 無料問題集「Oracle Java SE 21 Developer Professional」

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