1z0-830試験無料問題集（85題）「Oracle Java SE 21 Developer Professional 認定」

出題：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 --module-source-path src -p lib/com.eiffel.membership.jar -s out -m com.eiffeltower.shop

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

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

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

正解：B 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：2

Given:
java
Object myVar = 0;
String print = switch (myVar) {
case int i -> "integer";
case long l -> "long";
case String s -> "string";
default -> "";
};
System.out.println(print);
What is printed?

A. Compilation fails.

B. string

C. long

D. integer

E. nothing

F. It throws an exception at runtime.

正解：A 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：3

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

A. var b = 2, c = 3.0;

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

C. var h = (g = 7);

D. var e;

E. var d[] = new int[4];

F. var f = { 6 };

正解：A,D,E,F 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：4

Given:
java
public class ExceptionPropagation {
public static void main(String[] args) {
try {
thrower();
System.out.print("Dom Perignon, ");
} catch (Exception e) {
System.out.print("Chablis, ");
} finally {
System.out.print("Saint-Emilion");
}
}
static int thrower() {
try {
int i = 0;
return i / i;
} catch (NumberFormatException e) {
System.out.print("Rose");
return -1;
} finally {
System.out.print("Beaujolais Nouveau, ");
}
}
}
What is printed?

A. Beaujolais Nouveau, Chablis, Saint-Emilion

B. Beaujolais Nouveau, Chablis, Dom Perignon, Saint-Emilion

C. Rose

D. Saint-Emilion

正解：A 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：5

Given:
java
Stream<String> strings = Stream.of("United", "States");
BinaryOperator<String> operator = (s1, s2) -> s1.concat(s2.toUpperCase()); String result = strings.reduce("-", operator); System.out.println(result); What is the output of this code fragment?

A. -UNITEDSTATES

B. UnitedStates

C. United-States

D. -UnitedStates

E. United-STATES

F. -UnitedSTATES

G. UNITED-STATES

正解：F 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：6

Given:
java
List<String> frenchAuthors = new ArrayList<>();
frenchAuthors.add("Victor Hugo");
frenchAuthors.add("Gustave Flaubert");
Which compiles?

A. Map<String, List<String>> authorsMap5 = new HashMap<String, List<String>>(); java authorsMap5.put("FR", frenchAuthors);

B. Map<String, List<String>> authorsMap4 = new HashMap<String, ArrayList<String>>(); java authorsMap4.put("FR", frenchAuthors);

C. Map<String, ? extends List<String>> authorsMap2 = new HashMap<String, ArrayList<String>> (); java authorsMap2.put("FR", frenchAuthors);

D. Map<String, ArrayList<String>> authorsMap1 = new HashMap<>();
java
authorsMap1.put("FR", frenchAuthors);

E. var authorsMap3 = new HashMap<>();
java
authorsMap3.put("FR", frenchAuthors);

正解：A,B,E 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：7

Given:
java
String colors = "red\n" +
"green\n" +
"blue\n";
Which text block can replace the above code?

A. None of the propositions

B. java
String colors = """
red \t
green\t
blue \t
""";

C. java
String colors = """
red \s
green\s
blue \s
""";

D. java
String colors = """
red \
green\
blue \
""";

E. java
String colors = """
red
green
blue
""";

正解：E 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：8

Given:
java
public class BoomBoom implements AutoCloseable {
public static void main(String[] args) {
try (BoomBoom boomBoom = new BoomBoom()) {
System.out.print("bim ");
throw new Exception();
} catch (Exception e) {
System.out.print("boom ");
}
}
@Override
public void close() throws Exception {
System.out.print("bam ");
throw new RuntimeException();
}
}
What is printed?

A. bim bam boom

B. Compilation fails.

C. bim boom bam

D. bim bam followed by an exception

E. bim boom

正解：A 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

出題：9

Which of the following methods of java.util.function.Predicate aredefault methods?

A. test(T t)

B. not(Predicate<? super T> target)

C. negate()

D. isEqual(Object targetRef)

E. or(Predicate<? super T> other)

F. and(Predicate<? super T> other)

正解：C,E,F 解答を投票する

解説: (GoShiken メンバーにのみ表示されます)

1z0-830試験無料問題集「Oracle Java SE 21 Developer Professional 認定」