Oracle 1z0-830 試験概要:

Oracle 1z0-830 試験シラバストピック:

Oracle Java SE 21 Developer Professional 認定 1z0-830 試験問題：

問題 #1
What is the output of the following snippet? (Assume the file exists)
java
Path path = Paths.get("C:\\home\\joe\\foo");
System.out.println(path.getName(0));

A. IllegalArgumentException
B. C
C. Compilation error
D. home
E. C:

問題 #2
Given:
java
Map<String, Integer> map = Map.of("b", 1, "a", 3, "c", 2);
TreeMap<String, Integer> treeMap = new TreeMap<>(map);
System.out.println(treeMap);
What is the output of the given code fragment?

A. Compilation fails
B. {b=1, c=2, a=3}
C. {c=1, b=2, a=3}
D. {a=3, b=1, c=2}
E. {b=1, a=3, c=2}
F. {a=1, b=2, c=3}
G. {c=2, a=3, b=1}

問題 #3
Given:
java
LocalDate localDate = LocalDate.of(2020, 8, 8);
Date date = java.sql.Date.valueOf(localDate);
DateFormat formatter = new SimpleDateFormat(/* pattern */);
String output = formatter.format(date);
System.out.println(output);
It's known that the given code prints out "August 08".
Which of the following should be inserted as the pattern?

A. MM dd
B. MMMM dd
C. MMM dd
D. MM d

問題 #4
Given:
java
package vehicule.parent;
public class Car {
protected String brand = "Peugeot";
}
and
java
package vehicule.child;
import vehicule.parent.Car;
public class MiniVan extends Car {
public static void main(String[] args) {
Car car = new Car();
car.brand = "Peugeot 807";
System.out.println(car.brand);
}
}
What is printed?

A. Peugeot
B. An exception is thrown at runtime.
C. Compilation fails.
D. Peugeot 807

問題 #5
Given:
java
Optional o1 = Optional.empty();
Optional o2 = Optional.of(1);
Optional o3 = Stream.of(o1, o2)
.filter(Optional::isPresent)
.findAny()
.flatMap(o -> o);
System.out.println(o3.orElse(2));
What is the given code fragment's output?

A. Optional.empty
B. 1
C. Compilation fails
D. 2
E. Optional[1]
F. 0
G. An exception is thrown

解説：