Tag: technology

Quizzes (307) Questions (36705)

Questions Related to technology

Multiple choice technology

Given: 12. import java.io.*; 13. public class Forest implements Serializable { 14. private Tree tree = new Tree(); 15. public static void main(String [] args) { 16. Forest f = new Forest(); 17. try { 18. FileOutputStream fs = new FileOutputStream("Forest.ser"); 19. ObjectOutputStream os = new ObjectOutputStream(fs); 20. os.writeObject(f); os.close(); 21. } catch (Exception ex) { ex.printStackTrace(); } 22. } } 23. 24. class Tree { } What is the result?

  1. Compilation fails

  2. An exception is thrown at runtime.

  3. An instance of Forest is serialized.

  4. An instance of Forest and an instance of Tree are both serialized
Reveal answer Fill a bubble to check yourself
B Correct answer
Full explanation
Multiple choice technology

Assuming that the serializeBanana() and the deserializeBanana() methods will correctly use Java serialization and given: 13. import java.io.*; 14. class Food implements Serializable {int good = 3;} 15. class Fruit extends Food {int juice = 5;} 16. public class Banana extends Fruit { 17. int yellow = 4; 18. public static void main(String [] args) { 19. Banana b = new Banana(); Banana b2 = new Banana(); 20. b.serializeBanana(b); // assume correct serialization 21. b2 = b.deserializeBanana(); // assume correct 22. System.out.println("restore "+b2.yellow+ b2.juice+b2.good); 24. } 25. // more Banana methods go here 50. } What is the result?

  1. restore 400

  2. restore 403

  3. restore 453

  4. Compilation fails.

  5. An exception is thrown at runtime
Reveal answer Fill a bubble to check yourself
C Correct answer
Full explanation
Multiple choice technology

Given this method in a class: 21. public String toString() { 22. StringBuffer buffer = new StringBuffer(); 23. buffer.append('<'); 24. buffer.append(this.name); 25. buffer.append('>'); 26. return buffer.toString(); 27. } Which statement is true?

  1. This code is NOT thread-safe

  2. The programmer can replace StringBuffer with StringBuilder with no other changes

  3. This code will perform poorly. For better performance, the code should be rewritten:return "<" + this.name + ">";

  4. This code will perform well and converting the code to use StringBuilder will not enhance the performance
Reveal answer Fill a bubble to check yourself
B Correct answer
Full explanation
Multiple choice technology

Given: 1. package geometry; 2. public class Hypotenuse { 3. public InnerTriangle it = new InnerTriangle(); 4. class InnerTriangle { 5. public int base; 6. public int height; 7. } Which statement is true about the class of an object that can reference the variable base?

  1. It can be any class

  2. No class has access to base

  3. The class must belong to the geometry package

  4. The class must be a subclass of the class Hypotenuse
Reveal answer Fill a bubble to check yourself
C Correct answer
Full explanation
Multiple choice technology

Given: 10: public class Hello { 11: String title; 12: int value; 13: public Hello() { 14: title += " World"; 15: } 16: public Hello(int value) { 17: this.value = value; 18: title = "Hello"; 19: Hello(); 20: } 21: } and: 30: Hello c = new Hello(5); 31: System.out.println(c.title); What is the result

  1. Hello

  2. Hello World

  3. Compilation fails

  4. Hello World 5

  5. The code runs with no output.

  6. An exception is thrown at runtime
Reveal answer Fill a bubble to check yourself
C Correct answer
Full explanation
Multiple choice technology

Given: 1. interface A { public void aMethod(); } 2. interface B { public void bMethod(); } 3. interface C extends A,B { public void cMethod(); } 4. class D implements B { 5. public void bMethod(){} 6. } 7. class E extends D implements C { 8. public void aMethod(){} 9. public void bMethod(){} 10. public void cMethod(){} 11. } What is the result?

  1. Compilation fails because of an error in line 3

  2. Compilation fails because of an error in line 7

  3. Compilation fails because of an error in line 9

  4. If you define D e = new E(), then e.bMethod() invokes the version of bMethod() defined in Line 5.

  5. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 5.

  6. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 9.
Reveal answer Fill a bubble to check yourself
F Correct answer
Multiple choice technology

Given: 1. public class Base { 2. public static final String FOO = "foo"; 3. public static void main(String[] args) { 4. Base b = new Base(); 5. Sub s = new Sub(); 6. System.out.print(Base.FOO); 7. System.out.print(Sub.FOO); 8. System.out.print(b.FOO); 9. System.out.print(s.FOO); 10. System.out.print(((Base)s).FOO); 11. } } 12. class Sub extends Base {public static final String FOO="bar";} What is the result?

  1. foofoofoofoofoo

  2. foobarfoobarbar

  3. foobarfoofoofoo

  4. foobarfoobarfoo

  5. barbarbarbarbar

  6. foofoofoobarbar
Reveal answer Fill a bubble to check yourself
D Correct answer
Full explanation