Tag: web technology

Questions Related to web technology

In the UML notation, parameterized (generic) classes are represented by
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  1. the normal class representation with a dotted arrow pointing at the template parameter classes

  2. the normal class representation but shaded grey.

  3. the normal class representation with a dotted outline and the names of its parameter classes listed on the top right-hand corner.

  4. the normal class representation with a rectangular box in its top left-hand corner.

  5. Its a trick question - parameterized classes can't be specified in the UML notation.

Show answer
Correct Option: C

XML is Case-Sensitive Language
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  1. True

  2. False

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Correct Option: B

Given: public static void before() { Set set = new TreeSet(); set.add("2"); set.add(3); set.add("1"); Iterator it = set.iterator(); while (it.hasNext()) System.out.print(it.next() + " "); } Which statements are true?
technology web technology

  1. The before() method will print 1 2

  2. The before() method will print 1 2 3

  3. The before() method will print three numbers, but the order cannot be determined

  4. The before() method will not compile

  5. The before() method will throw an exception at runtime

Show answer
Correct Option: E

Given: interface Hungry { void munch(E x); } interface Carnivore extends Hungry {} interface Herbivore extends Hungry {} abstract class Plant {} class Grass extends Plant {} abstract class Animal {} class Sheep extends Animal implements Herbivore { public void munch(Sheep x) {} } class Wolf extends Animal implements Carnivore { public void munch(Sheep x) {} } Which of the following changes (taken separately) would allow this code to compile? (Choose all that apply.)
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  1. Change the Carnivore interface to interface Carnivore extends Hungry {}

  2. Change the Herbivore interface to interface Herbivore extends Hungry {}

  3. Change the Sheep class to class Sheep extends Animal implements Herbivore { public void munch(Grass x) {} }

  4. Change the Sheep class to class Sheep extends Plant implements Carnivore { public void munch(Wolf x) {} }

  5. Change the Wolf class to class Wolf extends Animal implements Herbivore { public void munch(Grass x) {} }

  6. No changes are necessary

Show answer
Correct Option: B

Which collection class(es) allows you to grow or shrink its size and provides indexed access to its elements, but whose methods are not synchronized? (Choose all that apply.)
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  1. java.util.HashSet

  2. java.util.LinkedHashSet

  3. java.util.List

  4. java.util.ArrayList

  5. java.util.Vector

  6. java.util.PriorityQueue

Show answer
Correct Option: D

Given: public static void main(String[] args) { // INSERT DECLARATION HERE for (int i = 0; i <= 10; i++) { List row = new ArrayList(); for (int j = 0; j <= 10; j++) row.add(i * j); table.add(row); } for (List row : table) System.out.println(row); } Which statements could be inserted at // INSERT DECLARATION HERE to allow this code to compile and run? (Choose all that apply.)
technology web technology

  1. List> table = new List>();

  2. List> table = new ArrayList>();

  3. List> table = new ArrayList>();

  4. List table = new List();

  5. List table = new ArrayList();

  6. List table = new ArrayList();

Show answer
Correct Option: B

Given: 3. import java.util.*; 4. class Business { } 5. class Hotel extends Business { } 6. class Inn extends Hotel { } 7. public class Travel { 8. ArrayList go() { 9. // insert code here 10. } 11. } Which, inserted independently at line 9, will compile? (Choose all that apply.)
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  1. return new ArrayList();

  2. return new ArrayList();

  3. return new ArrayList();

  4. return new ArrayList();

Show answer
Correct Option: B

Which is true? (Choose all that apply.)
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  1. "X extends Y" is correct if and only if X is a class and Y is an interface

  2. "X extends Y" is correct if and only if X is an interface and Y is a class

  3. "X extends Y" is correct if X and Y are either both classes or both interfaces

  4. "X extends Y" is correct for all combinations of X and Y being classes and/or interfaces

Show answer
Correct Option: C

Given: 3. class A { } 4. class B extends A { } 5. public class ComingThru { 6. static String s = "-"; 7. public static void main(String[] args) { 8. A[] aa = new A[2]; 9. B[] ba = new B[2]; 10. sifter(aa); 11. sifter(ba); 12. sifter(7); 13. System.out.println(s); 14. } 15. static void sifter(A[]... a2) { s += "1"; } 16. static void sifter(B[]... b1) { s += "2"; } 17. static void sifter(B[] b1) { s += "3"; } 18. static void sifter(Object o) { s += "4"; } 19. } What is the result?
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  1. -124

  2. -134

  3. -424

  4. -434

  5. -444

  6. Compilation fails

Show answer
Correct Option: D

Given: 3. public class Wind { 4. public static void main(String[] args) { 5. foreach: 6. for(int j=0; j<5; j++) { 7. for(int k=0; k< 3; k++) { 8. System.out.print(" " + j); 9. if(j==3 && k==1) break foreach; 10. if(j==0 || j==2) break; 11. } 12. } 13. } 14. } What is the result?
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  1. 0 1 2 3

  2. 1 1 1 3 3

  3. 0 1 1 1 2 3 3

  4. 1 1 1 3 3 4 4 4

  5. 0 1 1 1 2 3 3 4 4 4

  6. Compilation fails

Show answer
Correct Option: C