Tag: technology

Questions Related to technology

Click the Exhibit button. 1. public interface A { 2. public void doSomething(String thing); 3. } 1. public class AImpl implements A { 2. public void doSomething(String msg) { } 3. } 1. public class B { 2. public A doit() { 3. // more code here 4. } 5. 6. public String execute() { 7. // more code here 8. } 9. } 1. public class C extends B { 2. public AImpl doit() { 3. // more code here 4. } 5. 6. public Object execute() { 7. // more code here 8. } 9. } Which statement is true about the classes and interfaces in the exhibit?
technology programming languages

  1. Compilation will succeed for all classes and interfaces.

  2. Compilation of class C will fail because of an error in line 2.

  3. Compilation of class C will fail because of an error in line 6.

  4. Compilation of class AImpl will fail because of an error in line 2.

Show answer
Correct Option: C
Explanation:

To solve this question, users need to understand the concept of interfaces and inheritance in Java programming language.

  • The interface A declares a method called doSomething that takes a string parameter.
  • The class AImpl implements the A interface and provides an implementation for the doSomething method.
  • The class B declares a method called doit that returns an object of type A.
  • The class C extends B and declares a method called doit that returns an object of type AImpl. It also declares a method called execute that overrides the execute method in class B and returns an object of type Object.

Now let's go through each option:

A. Compilation will succeed for all classes and interfaces.

This option is incorrect. Although there are no syntax errors in the code, there is a logical error in class C. It overrides the doit method in class B with a method that returns AImpl instead of A. This violates the Liskov Substitution Principle, which states that subclasses should be substitutable for their base classes. As a result, compilation will fail for class C.

B. Compilation of class C will fail because of an error in line 2.

This option is incorrect. There are no syntax errors in line 2 of class C. The error is a logical error, as explained above.

C. Compilation of class C will fail because of an error in line 6.

This option is correct. The execute method in class C attempts to override the execute method in class B. However, the return type of the method in class C is Object, which is not a subtype of the return type of the method in class B, which is String. As a result, compilation will fail for class C.

D. Compilation of class AImpl will fail because of an error in line 2.

This option is incorrect. There are no syntax errors in line 2 of class AImpl.

Therefore, the correct answer is:

The Answer is: C. Compilation of class C will fail because of an error in line 6.

Click the Exhibit button. 1. public class A { 2. public String doit(int x, int y) { 3. return “a”; 4. } 5. 6. public String doit(int... vals) { 7. return “b”; 8. } 9. } Given: 25. A a=new A(); 26. System.out.println(a.doit(4, 5)); What is the result?
technology programming languages

  1. Line 26 prints “a” to System.out

  2. Line 26 prints ‘b” to System.out

  3. An exception is thrown at line 26 at runtime.

  4. Compilation of class A will fail due to an error in line 6

Show answer
Correct Option: A
Explanation:

To solve this question, the user should understand the concept of method overloading and how Java resolves the method call based on the number and type of arguments passed.

In the given code, class A has two methods named doit. One method takes two integer arguments, and the other takes an arbitrary number of integer arguments.

When we call a.doit(4,5) on line 26, Java examines both methods in class A that are named doit and checks to see which one matches the argument types. Since there is a doit method with two integer parameters, Java selects that method, and the String "a" is returned by that method.

Therefore, the output of the given code is:

The Answer is: A. Line 26 prints “a” to System.out.

Given: 1. public class A { 2. public void doit() { 3. } 4. public String doit() { 5. return “a”; 6. } 7. public double doit(int x) { 8. return 1.0; 9. } 10.} What is the result?

technology programming languages

  1. An exception is thrown at runtime

  2. Compilation fails because of an error in line 7

  3. Compilation fails because of an error in line 4.

  4. Compilation succeeds and no runtime errors with class A occur

Show answer
Correct Option: C

Given: 10. class Line { 11. public static class Point { } 12. } 13. 14. class Triangle { 15. // insert code here 16. } Which code, inserted at line 15, creates an instance of the Point class defined in Line?
technology programming languages

  1. Point p = new Point();

  2. Line.Point p = new Line.Point();

  3. The Point class cannot be instatiated at line 15

  4. Line 1 = new Line() ; 1.Point p = new 1.Point();

Show answer
Correct Option: B
Explanation:

To solve this question, the user needs to know how to create an instance of a nested class.

Option A: Point p = new Point(); This option is incorrect because the Point class is a nested static class and must be accessed through the outer class. In this case, the outer class is Line and the correct way to access the nested class is Line.Point.

Option B: Line.Point p = new Line.Point(); This option is correct. Since Point is a nested static class, it can be accessed using the outer class name followed by a dot and the nested class name. This option correctly creates an instance of the Point class defined in Line.

Option C: The Point class cannot be instantiated at line 15. This option is incorrect. The Point class can be instantiated from within the Triangle class, but it must be done using the correct syntax since it is a nested class.

Option D: Line 1 = new Line() ; 1.Point p = new 1.Point(); This option is incorrect because it contains a syntax error. The variable 1 cannot be used as a variable name in Java.

The Answer is: B. Line.Point p = new Line.Point();

Given: 10. class Line { 11. public class Point { public int x,y; } 12. public Point getPoint() { return new Point(); } 13. } 14. class Triangle { 15. public Triangle() { 16. // insert code here 17. } 18. } Which code, inserted at line 16, correctly retrieves a local instance of a Point object?
technology programming languages

  1. Point p = Line.getPoint();

  2. Line.Point p = Line.getPoint();

  3. Point p = (new Line()).getPoint();

  4. Line.Point p = (new Line()).getPoint();

Show answer
Correct Option: D

Given: 10. class One { 11. public One() { System.out.print(1); } 12. } 13. class Two extends One { 14. public Two() { System.out.print(2); } 15. } 16. class Three extends Two { 17. public Three() { System.out.print(3); } 18. } 19. public class Numbers{ 20. public static void main( String[] argv) { new Three(); } 21. } What is the result when this code is executed?
technology programming languages

  1. 1

  2. 3

  3. 123

  4. 321

Show answer
Correct Option: C

which datatype store pointer to binary file on disk
technology databases

  1. BLOB

  2. CLOB

  3. BFILE

  4. NCLOB

Show answer
Correct Option: C

For Which datatype Maximum size is 4GB
technology databases

  1. CLOB

  2. BLOB

  3. NCLOB

  4. ALL

Show answer
Correct Option: D

A) Long raw - Variable length binary strings B) LONG - Character data of variable length
technology databases

  1. A is correct

  2. B is correct

  3. A & B Both correct

  4. A & B both Incorrect

Show answer
Correct Option: C

32-bit floating point number datatype is?
technology databases

  1. BINARY_FLOAT

  2. BINARY_DOUBLE

  3. ROWID

  4. NCHAR

Show answer
Correct Option: A