Free Oracle 1z0-830 Study Guides Exam Questions & Answer [Q13-Q31]

NO.13 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?

NO.14 Which three of the following are correct about the Java module system?

NO.15 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?

NO.16 Given:
java
public class Test {
static int count;
synchronized Test() {
count++;
}
public static void main(String[] args) throws InterruptedException {
Runnable task = Test::new;
Thread t1 = new Thread(task);
Thread t2 = new Thread(task);
t1.start();
t2.start();
t1.join();
t2.join();
System.out.println(count);
}
}
What is the given program’s output?

NO.17 Given:
java
var array1 = new String[]{ “foo”, “bar”, “buz” };
var array2[] = { “foo”, “bar”, “buz” };
var array3 = new String[3] { “foo”, “bar”, “buz” };
var array4 = { “foo”, “bar”, “buz” };
String array5[] = new String[]{ “foo”, “bar”, “buz” };
Which arrays compile? (Select 2)

NO.18 Given:
java
List<Integer> integers = List.of(0, 1, 2);
integers.stream()
.peek(System.out::print)
.limit(2)
.forEach(i -> {});
What is the output of the given code fragment?

NO.19 Given:
java
var now = LocalDate.now();
var format1 = new DateTimeFormatter(ISO_WEEK_DATE);
var format2 = DateTimeFormatter.ISO_WEEK_DATE;
var format3 = new DateFormat(WEEK_OF_YEAR_FIELD);
var format4 = DateFormat.getDateInstance(WEEK_OF_YEAR_FIELD);
System.out.println(now.format(REPLACE_HERE));
Which variable prints 2025-W01-2 (present-day is 12/31/2024)?

NO.20 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”);
}
}

NO.21 Given:
java
System.out.print(Boolean.logicalAnd(1 == 1, 2 < 1));
System.out.print(Boolean.logicalOr(1 == 1, 2 < 1));
System.out.print(Boolean.logicalXor(1 == 1, 2 < 1));
What is printed?

NO.22 Given:
java
String colors = “redn” +
“greenn” +
“bluen”;
Which text block can replace the above code?

NO.23 Given:
java
var _ = 3;
var $ = 7;
System.out.println(_ + $);
What is printed?

NO.24 Which of the following can be the body of a lambda expression?

NO.25 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?

NO.26 Given:
java
import java.io.*;
class A implements Serializable {
int number = 1;
}
class B implements Serializable {
int number = 2;
}
public class Test {
public static void main(String[] args) throws Exception {
File file = new File(“o.ser”);
A a = new A();
var oos = new ObjectOutputStream(new FileOutputStream(file));
oos.writeObject(a);
oos.close();
var ois = new ObjectInputStream(new FileInputStream(file));
B b = (B) ois.readObject();
ois.close();
System.out.println(b.number);
}
}
What is the given program’s output?

NO.27 Consider the following methods to load an implementation of MyService using ServiceLoader. Which of the methods are correct? (Choose all that apply)

NO.28 Given:
java
int post = 5;
int pre = 5;
int postResult = post++ + 10;
int preResult = ++pre + 10;
System.out.println(“postResult: ” + postResult +
“, preResult: ” + preResult +
“, Final value of post: ” + post +
“, Final value of pre: ” + pre);
What is printed?

NO.29 Which of the following statements is correct about a final class?

NO.30 Given:
java
var sList = new CopyOnWriteArrayList<Customer>();
Which of the following statements is correct?

NO.31 Given:
java
void verifyNotNull(Object input) {
boolean enabled = false;
assert enabled = true;
assert enabled;
System.out.println(input.toString());
assert input != null;
}
When does the given method throw a NullPointerException?