Oracle 1Z0-804 Online Practice Questions and Exam Preparation

Oracle 1Z0-804 Online Questions & Answers

• Question 141:

  Given the two Java classes:

  public class Word {

  private Word(int length) {}

  protected Word(String w) {}

  }

  public class Buzzword extends Word {

  public Buzzword() {

  // Line ***, add code here

  }

  public Buzzword(String s) {

  super(s);

  }

  }

  Which two code snippets, added independently at line ***, can make the Buzzword class compile?

  A. this ();
  B. this (100);
  C. this ("Buzzword");
  D. super ();
  E. super (100);
  F. super ("Buzzword");
  A. this ();
  F. super ("Buzzword");

• Question 142:

  Which two are valid initialization statements?

  A. Map m = new SortedMap();
  B. Collection m = new TreeMap();
  C. HashMap m = new SortedMap();
  D. SortedMap m = new TreeMap ();
  E. Hashtable m = new HashMap();
  F. Map m = new Hashtable();
  D. SortedMap m = new TreeMap ();
  F. Map m = new Hashtable();

• Question 143:

  Given:

  

  Which two statements concerning the OO concepts "is-a" and "has-a" are true?

  A. Flimmer is-a Glommer.
  B. Flommer has-a String.
  C. Tagget has-a Glommer.
  D. Flimmer is-a ArrayList.
  E. Tagget has-a doStuff()
  F. Tagget is-a Glommer.
  B. Flommer has-a String.
  F. Tagget is-a Glommer.

  ---

  B: The relationship modeled by composition is often referred to as the "has-a" relationship. Here Flommer has-a String.

  E: The has-a relationship has an encapsulation feature (like private or protected modifier used before each member field or method). Here Tagget has-a method doStuff()

  F: Tagget implements Glommer. Tagget is-a Glommer.

  Note: The has-a relationship has an encapsulation feature (like private or protected modifier used before each member field or method).

• Question 144:

  Given:

  class Car implements TurboVehicle, Steerable {

  // Car methods > interface Convertible

  {

  // Convertible methods

  }

  public class SportsCar extends Car implements Convertible {

  }

  Which statement is true?

  A. SportsCar must implement methods from TurboVehicle and steerable
  B. SportsCar must override methods defined by car.
  C. SportsCar must implement methods define by convertible.
  D. Instances of car can invoke convertible methods.
  C. SportsCar must implement methods define by convertible.

  ---

  To declare a class that implements an interface, you include an implements clause in the class declaration.

  By convention, theimplements clause follows the extends clause, if there is one.

  Here are the some point that must be considered while implementing an interface (or interfaces) into a java class.

  A class implementing an interface must either implement all the methods of that interface otherwise known as the abstract class.

  A class in java may extend at most one superclass because java does not allow multiple inheritance, by it may implement more than one interface.

  Multiple inheritance in java is achieved through the interfaces.

  When a class implements more than one interface then implement statement requires a comma-separated list of interfaces to be implement by that class.

• Question 145:

  Given the code fragment:

  DataFormat df;

  Which statement defines a new Dateformat object that displays the default date format for the UK Locale?

  A. df = DateFormat.getdatDataInstance (DateFormat.DEFAULT, Locale (UK));
  B. df = DateFormat.getdatDataInstance (DateFormat.DEFAULT, UK);
  C. df = DateFormat.getdatDataInstance (DateFormat.DEFAULT, Locale.UK);
  D. df = new DateFormat.getdatDataInstance (DateFormat.DEFAULT, Locale.UK);
  E. df = new DateFormat.getdatDataInstance (DateFormat.DEFAULT, Locale (UK));
  C. df = DateFormat.getdatDataInstance (DateFormat.DEFAULT, Locale.UK);

  ---

  The UK locale is constructed with Locale.UK.

  Example:

  To format a date for a different Locale, specify it in the call to getDateInstance().

  DateFormat df = DateFormat.getDateInstance(DateFormat.LONG, Locale.FRANCE);

  Note: getDateInstance(int style, Locale aLocale)

  Gets the date formatter with the given formatting style for the given locale.

  Reference: Class DateFormat

• Question 146:

  Which three are true?

  A. A setAutoCommit (False) method invocation starts a transaction context.
  B. An instance of savepoint represents a point in the current transaction context.
  C. A rollback () method invocation rolls a transaction back to the last savepoint.
  D. A rollback () method invocation releases any database locks currently held by this connection object.
  E. After calling rollback (mysavepoint), you must close the savepoint object by calling mySavepoint.close() .
  A. A setAutoCommit (False) method invocation starts a transaction context.
  B. An instance of savepoint represents a point in the current transaction context.
  C. A rollback () method invocation rolls a transaction back to the last savepoint.

  ---

  A: The way to allow two or more statements to be grouped into a transaction is to disable the auto-commit mode. After the auto-commit mode is disabled, no SQL statements are committed until you call the method commit explicitly. All statements executed after the previous call to the method commit are included in the current transaction and committed together as a unit.

  Note: When a connection is created, it is in auto-commit mode. This means that each individual SQL statement is treated as a transaction and is automatically committed right after it is executed. (To be more precise, the default is for a SQL statement to be committed when it is completed, not when it is executed. A statement is completed when all of its result sets and update counts have been retrieved. In almost all cases, however, a statement is completed, and therefore committed, right after it is executed.)

  B: The method Connection.setSavepoint, sets a Savepoint object within the current transaction. The Connection.rollback method is overloaded to take a Savepoint argument.

  C: calling the method rollback terminates a transaction and returns any values that were modified to their previous values. If you are trying to execute one or more statements in a transaction and get a SQLException, call the method rollback to end the transaction and start the transaction all over again.

• Question 147:

  Given:

  

  What is the result?

  A. fast slow
  B. fast goes
  C. goes goes
  D. fast fast
  E. fast followed by an exception
  F. Compilation fails
  F. Compilation fails

  ---

  Line: Vehicle v = new Sportscar(); causes compilation failure:

  error: cannot find symbol Vehicle v = new Sportscar(); symbol: class Sportscar location: class VehicleTest

• Question 148:

  Given:

  import java.util.concurrent.atomic.AtomicInteger;

  public class Incrementor {

  public static void main(String[] args) {

  AtomicInteger[] var = new AtomicInteger[5];

  for (int i = 0; i < 5; i++) {

  var[i] = new AtomicInteger();

  }

  for (int i =0; i < var.length; i++) {

  var[i].incrementAndGet();

  if (i ==2)

  var[i].compareAndSet(2,4);

  System.out.print(var[i] + " ");

  }

  }

  }

  What is the result?

  A. 1 1 1 1 1
  B. 1 2 3 4 5
  C. 0 1 2 3 4
  D. 0 1 4 3 4
  A. 1 1 1 1 1

• Question 149:

  Given:

  

  Which three statements concerning the OO concepts "is-a" and "has-a" are true?

  A. Flimmer is-a Plinkable
  B. Flommer has-a Tagget
  C. Flommer is-a Glommer
  D. Tagget has-a String
  E. Flommer is-a Plinkable
  F. Flimmer is-a Flommer
  G. Tagget is-a Plinkable
  A. Flimmer is-a Plinkable
  D. Tagget has-a String
  F. Flimmer is-a Flommer

  ---

  A: Flimmer implements Plinkable.

  Flimmer is-a plinkable.

  D: The relationship modeled by composition is often referred to as the "has-a" relationship.

  Here Tagget has-a String.

  F: Flommer extends Flimmer

  So there is an "is-a relationship between Flommer and Flimmer .

  Note: The has-a relationship has an encapsulation feature (like private or protected modifier used before each member field or method).

• Question 150:

  Given:

  public class SleepOtherThread {

  public static void main(String[] args) throws InterruptedException {

  Runnable r = new Runnable() {

  public void run() {

  System.out.print(Thread.currentThread().getName());

  }

  };

  Thread t1 = new Thread(r, "One ");

  t1.start();

  t1.sleep(2000);

  Thread t2 = new Thread(r, "Two ");

  t2.start();

  t2.sleep(1000);

  System.out.print("Main ");

  }

  }

  What is the most likely result?

  A. Main One Two
  B. Main Two One
  C. One Two Main
  D. One Main Two
  E. Two Main One
  C. One Two Main