最新的高品質 1z0-830 考試練習題庫

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最新的 Java SE 1z0-830 免費考試真題：

1. 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) MMM dd
B) MMMM dd
C) MM dd
D) MM d

2. Given:
java
public class ThisCalls {
public ThisCalls() {
this(true);
}
public ThisCalls(boolean flag) {
this();
}
}
Which statement is correct?

A) It throws an exception at runtime.
B) It compiles.
C) It does not compile.

3. 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) 1
B) Optional.empty
C) Optional[1]
D) 0
E) An exception is thrown
F) Compilation fails
G) 2

4. 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) It throws an exception at runtime.
B) Compilation fails.
C) long
D) string
E) nothing
F) integer

5. Which two of the following aren't the correct ways to create a Stream?

A) Stream stream = Stream.ofNullable("a");
B) Stream stream = Stream.generate(() -> "a");
C) Stream<String> stream = Stream.builder().add("a").build();
D) Stream stream = Stream.empty();
E) Stream stream = new Stream();
F) Stream stream = Stream.of();

問題與答案：