Oracle Oracle Database 1Z0-809 Questions & Answers

• Question 191:

  Given the code fragment:

  public void recDelete (String dirName) throws IOException {

  File [ ] listOfFiles = new File (dirName) .listFiles();

  if (listOfFiles ! = null andand listOfFiles.length >0) {

  for (File aFile : listOfFiles) {

  if (aFile.isDirectory ()) {

  recDelete (aFile.getAbsolutePath ());

  } else {

  if (aFile.getName ().endsWith (".class"))

  aFile.delete ();

  }

  }

  }

  }

  Assume that Projects contains subdirectories that contain .class files and is passed as an argument to the

  recDelete () method when it is invoked.

  What is the result?

  A. The method deletes all the .class files in the Projects directory and its subdirectories.

  B. The method deletes the .class files of the Projects directory only.

  C. The method executes and does not make any changes to the Projects directory.

  D. The method throws an IOException.

  Correct Answer: A

• Question 192:

  Given the code fragments:

  4.

  void doStuff() throws ArithmeticException, NumberFormatException, Exception {

  5.

  if (Math.random() >-1 throw new Exception ("Try again");

  6.

  }

  and

  24.

  try {

  25.

  doStuff ( ):

  26.

  } catch (ArithmeticException | NumberFormatException | Exception e) {

  27.

  System.out.println (e.getMessage()); }

  28.

  catch (Exception e) {

  29.

  System.out.println (e.getMessage()); }

  30.

  }

  Which modification enables the code to print Try again?

  A. Comment the lines 28, 29 and 30.

  B. Replace line 26 with: } catch (Exception | ArithmeticException | NumberFormatException e) {

  C. Replace line 26 with: } catch (ArithmeticException | NumberFormatException e) {

  D. Replace line 27 with: throw e;

  Correct Answer: C

• Question 193:

  Given the definition of the Country class:

  public class country {

  public enum Continent {ASIA, EUROPE}

  String name;

  Continent region;

  public Country (String na, Continent reg) {

  name = na, region = reg;

  }

  public String getName () {return name;}

  public Continent getRegion () {return region;}

  }

  and the code fragment:

  List couList = Arrays.asList (

  new Country ("Japan", Country.Continent.ASIA),

  new Country ("Italy", Country.Continent.EUROPE),

  new Country ("Germany", Country.Continent.EUROPE));

  Map> regionNames = couList.stream ()

  .collect(Collectors.groupingBy (Country ::getRegion,

  Collectors.mapping(Country::getName, Collectors.toList()))));

  System.out.println(regionNames);

  A. {EUROPE = [Italy, Germany], ASIA = [Japan]}

  B. {ASIA = [Japan], EUROPE = [Italy, Germany]}

  C. {EUROPE = [Germany, Italy], ASIA = [Japan]}

  D. {EUROPE = [Germany], EUROPE = [Italy], ASIA = [Japan]}

  Correct Answer: B

• Question 194:

  Given the code fragment:

  Map books = new TreeMap<>();

  books.put (1007, "A");

  books.put (1002, "C");

  books.put (1001, "B");

  books.put (1003, "B");

  System.out.println (books);

  What is the result?

  A. {1007 = A, 1002 = C, 1001 = B, 1003 = B}

  B. {1001 = B, 1002 = C, 1003 = B, 1007 = A}

  C. {1002 = C, 1003 = B, 1007 = A}

  D. {1007 = A, 1001 = B, 1003 = B, 1002 = C}

  Correct Answer: B

  Reference: TreeMap inherits SortedMap and automatically sorts the element's key

• Question 195:

  Given:

  class Book {

  int id;

  String name;

  public Book (int id, String name) {

  this.id = id;

  this.name = name;

  }

  public boolean equals (Object obj) { //line n1

  boolean output = false;

  Book b = (Book) obj;

  if (this.name.equals(b name))}

  output = true;

  }

  return output;

  }

  }

  and the code fragment:

  Book b1 = new Book (101, "Java Programing");

  Book b2 = new Book (102, "Java Programing");

  System.out.println (b1.equals(b2)); //line n2

  Which statement is true?

  A. The program prints true.

  B. The program prints false.

  C. A compilation error occurs. To ensure successful compilation, replace line n1 with: boolean equals (Book obj) {

  D. A compilation error occurs. To ensure successful compilation, replace line n2 with: System.out.println (b1.equals((Object) b2));

  Correct Answer: A

• Question 196:

  Given the content of Operator.java, EngineOperator.java, and Engine.java files: and the code fragment:

  

  

  What is the result?

  A. The Engine.java file fails to compile.

  B. The EngineOperator.java file fails to compile.

  C. The Operator.java file fails to compile.

  D. ON OFF

  Correct Answer: A

• Question 197:

  Given the code fragment:

  Stream> iStr= Stream.of (

  Arrays.asList ("1", "John"),

  Arrays.asList ("2", null)0;

  Stream< nInSt = iStr.flatMapToInt ((x) -> x.stream ());

  nInSt.forEach (System.out :: print);

  What is the result?

  A. 1John2null

  B. 12

  C. A NullPointerException is thrown at run time.

  D. A compilation error occurs.

  Correct Answer: D

• Question 198:

  Given the code fragment:

  Path file = Paths.get ("courses.txt"); // line n1

  Assume the courses.txt is accessible.

  Which code fragment can be inserted at line n1 to enable the code to print the content of the courses.txt file?

  A. List fc = Files.list(file); fc.stream().forEach (s - > System.out.println(s));

  B. Stream fc = Files.readAllLines (file); fc.forEach (s - > System.out.println(s));

  C. List fc = readAllLines(file); fc.stream().forEach (s - > System.out.println(s));

  D. Stream fc = Files.lines (file); fc.forEach (s - > System.out.println(s));

  Correct Answer: D

• Question 199:

  Given:

  class Bird {

  public void fly () { System.out.print("Can fly"); }

  }

  class Penguin extends Bird {

  public void fly () { System.out.print("Cannot fly"); }

  }

  and the code fragment:

  class Birdie {

  public static void main (String [ ] args) {

  fly( ( ) -> new Bird ( ));

  fly (Penguin : : new);

  }

  /* line n1 */

  }

  Which code fragment, when inserted at line n1, enables the Birdie class to compile?

  A. static void fly (Consumer bird) { bird :: fly (); } {

  B. static void fly (Consumer bird) bird.accept( ) fly (); } {

  C. static void fly (Supplier bird) bird.get( ) fly (); } {

  D. static void fly (Supplier bird) LOST

  Correct Answer: C

• Question 200:

  Given:

  1.

  abstract class Shape {

  2.

  Shape ( ) { System.out.println ("Shape"); }

  3.

  protected void area ( ) { System.out.println ("Shape"); }

  4.

  }

  5.

  6.

  class Square extends Shape {

  7.

  int side;

  8.

  Square int side {

  9.

  /* insert code here */

  10.

  this.side = side;

  11.

  }

  12.

  public void area ( ) { System.out.println ("Square"); }

  13.

  }

  14.

  class Rectangle extends Square {

  15.

  int len, br;

  16.

  Rectangle (int x, int y) {

  17.

  /* insert code here */

  18.

  len = x, br = y;

  19.

  }

  20.

  void area ( ) { System.out.println ("Rectangle"); }

  21.

  }

  Which two modifications enable the code to compile? (Choose two.)

  A. At line 1, remove abstract

  B. At line 9, insert super ( );

  C. At line 12, remove public

  D. At line 17, insert super (x);

  E. At line 17, insert super (); super.side = x;

  F. At line 20, use public void area ( ) {

  Correct Answer: DF