Tag: programming languages

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Questions Related to programming languages

Multiple choice technology programming languages

Click the Exhibit button. Class TestException 1. public class TestException extends Exception { 2. } Class A: 1. public class A { 2. 3. public String sayHello(String name) throws TestException { 4. 5. if(name == null) { 6. throw new TestException(); 7. } 8. 9. return “Hello “+ name; 10. } 11. 12. } A programmer wants to use this code in an application: 45. A a=new A(); 46. System.out.println(a.sayHello(”John”)); Which two are true? (Choose two.)

  1. Class A will not compile.

  2. Line 46 can throw the unchecked exception TestException.

  3. Line 45 can throw the unchecked exception TestException.

  4. Line 46 will compile if the enclosing method throws a TestException.

  5. Line 46 will compile if enclosed in a try block, where TestException
Reveal answer Fill a bubble to check yourself
D,E Correct answer
Full explanation
Multiple choice technology programming languages

Given: public class NamedCounter { private final String name; private int count; public NamedCounter(String name) { this.name = name; } public String getName() { return name; } public void increment() { coount++; } public int getCount() { return count; } public void reset() { count = 0; } } Which three changes should be made to adapt this class to be used safely by multiple threads? (Choose three.)

  1. declare reset() using the synchronized keyword

  2. declare getName() using the synchronized keyword

  3. declare getCount() using the synchronized keyword

  4. declare the constructor using the synchronized keyword

  5. declare increment() using the synchronized keyword
Reveal answer Fill a bubble to check yourself
A,C,E Correct answer
Full explanation
Multiple choice technology programming languages

Click the Exhibit button. 1. import java.util.*; 2. 3. public class NameList { 4. private List names = new ArrayList(); 5. public synchronized void add(String name) { names.add(name); } 6. public synchronized void printAll() { 7. for (int i = 0; i

  1. An exception may be thrown at runtime.

  2. The code may run with no output, without exiting.

  3. The code may run with no output, exiting normally.

  4. The code may rum with output “A B A B C C “, then exit.

  5. The code may rum with output “A B C A B C A B C “, then exit.

  6. The code may ruin with output “A B C A A B C A B C “, then exit.
Reveal answer Fill a bubble to check yourself
E,F Correct answer
Full explanation
Multiple choice technology programming languages

Click the Exhibit button. 10. public class Transfers { 11. public static void main(String[] args) throws Exception { 12. Record r1 = new Record(); 13. Record r2 = new Record(); 14. doTransfer(r1, r2, 5); 15. doTransfer(r2, r1, 2); 16. doTransfer(r1, r2, 1); 17. // print the result 18. System.out.println(”rl = “ + r1.get() +“, r2=” + r2.get()); 19. } 20. private static void doTransfer( 21. final Record a, final Record b, final int amount) { 22. Thread t = new Thread() { 23. public void run() { 24. new Clerk().transfer(a, b, amount); 25. } 26. }; 27. t.start(); 28. } 29. } 30. class Clerk { 31. public synchronized void transfer(Record a, Record b, int amount){ 32. synchronized (a) { 33. synchronized (b) { 34. a.add(-amount); 35. b.add(amount); 36. } 37. } 38. } 39. } 40. class Record { 41.int num=10; 42. public int get() { return num; } 43. public void add(int n) { num = num + n; } 44. } If Transfers.main() is run, which three are true? (Choose three.)

  1. The output may be “r1 = 6, r2 = 14”.

  2. The output may be “r1 = 5, r2 = 15”.

  3. The output may be “r1 = 8, r2 = 12”.

  4. The code may run (and complete) with no output.

  5. The code may deadlock (without completing) with no output.

  6. M IllegalStateException or InterruptedException may be thrown at
Reveal answer Fill a bubble to check yourself
A,B,E Correct answer
Full explanation
Multiple choice technology programming languages

Given: 11. class ClassA {} 12. class ClassB extends ClassA {} 13. class ClassC extends ClassA {} and: 21. ClassA p0 = new ClassA(); 22. ClassB p1 = new ClassB(); 23. ClassC p2 = new ClassC(); 24. ClassA p3 = new ClassB(); 25. ClassA p4 = new ClassC(); Which three are valid? (Choose three.)

  1. p0 = p1;

  2. p1 =p2;

  3. p2 = p4;

  4. p2 = (ClassC)p1;

  5. p1 = (ClassB)p3;

  6. p2 = (ClassC)p4;
Reveal answer Fill a bubble to check yourself
A,E,F Correct answer
Full explanation
Multiple choice technology programming languages

Click the Exhibit button. 1. public class Car { 2. private int wheelCount; 3. private String vin; 4. public Car(String vin) { 5. this.vin = vin; 6. this.wheelCount = 4; 7. } 8. public String drive() { 9. return “zoom-zoom”; 10. } 11. public String getInfo() { 12. return “VIN: “+ vin + “wheels: “+ wheelCount; 13. } 14. } And: 1. public class MeGo extends Car { 2. public MeGo(String vin) { 3. this.wheelCount = 3; 4. } 5. } What two must the programmer do to correct the compilation errors? (Choose two.)

  1. insert a call to this() in the Car constructor

  2. insert a call to this() in the MeGo constructor

  3. insert a call to super() in the MeGo constructor

  4. insert a call to super(vin) in the MeGo constructor

  5. change the wheelCount variable in Car to protected

  6. change line 3 in the MeGo class to super.wheelCount = 3;
Reveal answer Fill a bubble to check yourself
D,E Correct answer
Full explanation
Multiple choice technology programming languages

Given: 1. public class Blip { 2. protected int blipvert(int x) { return 0; } 3. } 4. class Vert extends Blip { 5. // insert code here 6. } Which five methods, inserted independently at line 5, will compile? (Choose five.)

  1. public int blipvert(int x) { return 0; }

  2. protected long blipvert(int x, int y) { return 0; }

  3. private int blipvert(long x) { return 0; }

  4. protected long blipvert(int x) { return 0; }

  5. protected int blipvert(long x) { return 0; }

  6. protected long blipvert(long x) { return 0; }
Reveal answer Fill a bubble to check yourself
A,B,C,E,F Correct answer
Full explanation