1z0-819 practice test

1. Question 1 · 1

   Given TripleThis.java: Compiling TripleThis.java gives this compiler warning: Note: TripleThis.java uses unchecked or unsafe operations. Which two replacements remove this compiler warning and prints 12? (Choose two.)

   Choose all answers that apply.

   

   • Replace line 12 with public static void printValue(Function f, int num) {
   • Replace line 12 with public static void printValue(Function f, T num) {
   • Replace line 9 with Function tripler = x —> { return (Integer) x * 3; }
   • Replace line 12 with public static void printValue(Function f, Integer num) {
   • Replace line 9 with Function tripler = x -> { return x * 3; }
   • Replace line 9 with Function tripler = x -> [ return x * 3; ]

2. Question 2 · 1

   Given the code fragment: What change on line 1 will make this code compile?

   Choose one answer.

   

   • Add catch(M | L e)
   • Add catch(L e)
   • Add catch(N | L | M e)
   • Add catch(L | N e)
   • Add catch(L | M | N e)

3. Question 3 · 1

   Given the code fragment: Which two code snippets inserted independently inside println method print Mondial:domainmodel? (Choose two.)

   Choose all answers that apply.

   

   • Main.prefix + Main.name
   • prefix + getName
   • Main.prefix + Main.getName()
   • new Main().prefix + new Main().name
   • prefix + name
   • prefix + Main.name

4. Question 4 · 1

   Given: Automobile.java - Car.java - What must you do so that the code prints 4?

   Choose one answer.

   

   

   • Remove the parameter from wheels method in line 3.
   • Remove abstract keyword in line 1.
   • Replace the code in line 2 with Car ob = new Car();.
   • Add @Override annotation at line 2.

5. Question 5 · 1

   Which module is required for any application using Swing or AWT?

   Choose one answer.

   • java.desktop
   • java.prefs
   • java.se
   • java.logging
   • java.rmi

6. Question 6 · 1

   Which set of commands is necessary to create and run a custom runtime image from Java source files?

   Choose one answer.

   • java,jdeps
   • javac,jlink
   • javac,jar
   • jar,jlink

7. Question 7 · 1

   Given the code fragment: Which would cause s to be AQCD?

   Choose one answer.

   

   • s.replace(s.indexOf("B"), s.indexOf("B"), "Q");
   • s.replace(s.indexOf("A"), s.indexOf("B"), "Q");
   • s.replace(s.indexOf("B"), s.indexOf("C"), "Q");
   • s.replace(s.indexOf("A"), s.indexOf("C"), "Q");

8. Question 8 · 1

   Given: and What is the result?

   Choose one answer.

   

   

   • test:null
   • test:1
   • A ClassCastException is thrown at runtime.
   • null:null
   • The compilation fails.

9. Question 9 · 1

   Given: Given the directory structure: Given the commands to execute at the Test directory prompt: Which statement is true?

   Choose one answer.

   

   

   

   • Create an empty module-info.java file in the Test directory and on execution of the given commands, the program prints:
   • On execution of the given commands, the program prints:
   • Execute java --module-path pac pac.Hello instead of java -cp pac pac.Hello and on execution the program prints:
   • On execution of the given commands, the program prints:

10. Question 10 · 1

    Given: and What is the result?

    Choose one answer.

    

    

    • 214
    • 2341
    • 234
    • 2134

11. Question 11 · 1

    Given: What is the output?

    Choose one answer.

    

    • A NullPointerException is thrown at run time.
    • null
    • Duke
    • A NoSuchElementException is thrown at run time.

12. Question 12 · 1

    Given: Taking into account that the order of the elements is unpredictable, what is the output?

    Choose one answer.

    

    • {am=2, first=1, mismatch=1, second=2}
    • {mismatch=2, am=2, first=1, second=1}
    • {l=mismatch, 2=am}
    • {mismatch=1, am=2, first=1, second=1}

13. Question 13 · 1

    Given these declarations: and these two code fragments: Fragment 1: Fragment 2: Which code fragment is preferred and why?

    Choose one answer.

    

    

    

    • Fragment 1 because it is shorter.
    • Fragment 2 because it prevents SQL injection.
    • Fragment 2 because it explicitly specifies the SQL types of the column values.
    • Fragment 1 because it is more performant.

14. Question 14 · 1

    Given: How many LocalDate objects are created in this example?

    Choose one answer.

    

    • 2
    • 3
    • 4
    • 5

15. Question 15 · 1

    Given: You want to calculate the average of the Player’s score. Which statement inserted on line 1 will accomplish this?

    Choose one answer.

    

    • players.stream().average().orElse(0.0);
    • players.stream().mapToInt(a -> a.score).average().orElse(0.0);
    • players.stream().mapToDouble(a -> a.score).average();
    • players.stream().map(a -> a.score).average();

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