最新の1z0-830問題集で試験を準備する

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：

1. 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) An exception is thrown at runtime.
B) Compilation fails.
C) {}
D) {2=Crazy Horse, 3=Paradis Latin, 4=Le Lido}
E) CopyEdit{2=Crazy Horse, 3=Paradis Latin, 4=Le Lido, 5=Folies Bergere}

2. Which three of the following are correct about the Java module system?

A) If a request is made to load a type whose package is not defined in any known module, then the module system will attempt to load it from the classpath.
B) The unnamed module exports all of its packages.
C) We must add a module descriptor to make an application developed using a Java version prior to SE9 run on Java 11.
D) Code in an explicitly named module can access types in the unnamed module.
E) If a package is defined in both a named module and the unnamed module, then the package in the unnamed module is ignored.
F) The unnamed module can only access packages defined in the unnamed module.

3. 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) 42 42
C) 666 666
D) Compilation fails

4. Which StringBuilder variable fails to compile?
java
public class StringBuilderInstantiations {
public static void main(String[] args) {
var stringBuilder1 = new StringBuilder();
var stringBuilder2 = new StringBuilder(10);
var stringBuilder3 = new StringBuilder("Java");
var stringBuilder4 = new StringBuilder(new char[]{'J', 'a', 'v', 'a'});
}
}

A) stringBuilder4
B) stringBuilder3
C) stringBuilder1
D) stringBuilder2
E) None of them

5. Given:
java
interface A {
default void ma() {
}
}
interface B extends A {
static void mb() {
}
}
interface C extends B {
void ma();
void mc();
}
interface D extends C {
void md();
}
interface E extends D {
default void ma() {
}
default void mb() {
}
default void mc() {
}
}
Which interface can be the target of a lambda expression?

A) A
B) C
C) B
D) None of the above
E) E
F) D

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