Tag: programming languages

Questions Related to programming languages

Which method names follow the JavaBeans standard? (Choose all that apply.)
technology programming languages

  1. addSize

  2. getCust

  3. deleteRep

  4. isColorado

  5. putDimensions

Show answer
Correct Option: B,D

Which are valid declarations? (Choose all that apply.)

technology programming languages

  1. int $x;

  2. int 123;

  3. int _123;

  4. int #dim;

  5. int %percent;

  6. int central_sales_region_Summer_2005_gross_sales;

Show answer
Correct Option: A,C,F

AI Explanation

To determine which declarations are valid, we need to consider the rules for naming variables in programming languages like C++.

A. int $x; - This declaration is valid. In C++, variable names can start with a letter, underscore, or a dollar sign.

B. int 123; - This declaration is invalid. Variable names cannot start with a digit.

C. int _123; - This declaration is valid. Variable names can start with an underscore.

D. int #dim; - This declaration is invalid. Variable names cannot start with a special character like a hash or pound sign.

E. int %percent; - This declaration is invalid. Variable names cannot start with a special character like a percent sign.

F. int central_sales_region_Summer_2005_gross_sales; - This declaration is valid. Variable names can contain letters, numbers, and underscores.

Therefore, the valid declarations are A, C, and F.

Given: 

1. enum A { A } 
2. class E2 { 
3.   enum B { B } 
4.   void C() { 
5.     enum D { D } 
6.   } 
7. }

Which statements are true? (Choose all that apply.)

technology programming languages

  1. If only line 1 is removed the code compiles.

  2. If only line 3 is removed the code compiles.

  3. If only line 5 is removed the code compiles.

  4. If lines 1 and 3 are removed the code compiles

  5. If lines 1, 3 and 5 are removed the code compiles.

Show answer
Correct Option: C,E

AI Explanation

To answer this question, we need to understand the rules and restrictions regarding the declaration and usage of enums in Java.

In Java, an enum is a special data type that allows for a variable to be a set of predefined constants. Each constant is defined within the enum. Enums can only be declared at the top level of a class or interface, or within a class (as a member) but not inside a method.

Let's go through each option to understand why it is correct or incorrect:

Option A) If only line 1 is removed the code compiles. This option is incorrect because removing line 1 would remove the declaration of enum A. Since enum A is not used in the code, its removal does not affect the compilation.

Option B) If only line 3 is removed the code compiles. This option is incorrect because removing line 3 would remove the declaration of enum B. However, enum B is used within the class E2, so its removal would result in a compilation error.

Option C) If only line 5 is removed the code compiles. This option is correct because removing line 5 would remove the declaration of enum D, which is a local enum declared inside the method C(). Since enum D is not used outside of the method, its removal does not affect the compilation.

Option D) If lines 1 and 3 are removed the code compiles. This option is incorrect because removing line 1 would remove the declaration of enum A, and removing line 3 would remove the declaration of enum B. Since enum B is used within the class E2, its removal would result in a compilation error.

Option E) If lines 1, 3, and 5 are removed the code compiles. This option is correct because removing line 1 would remove the declaration of enum A, removing line 3 would remove the declaration of enum B, and removing line 5 would remove the declaration of enum D. Since enum B is used within the class E2, its removal would result in a compilation error. However, since enum D is a local enum declared inside the method C(), its removal does not affect the compilation.

Therefore, the correct answer is: C. If only line 5 is removed the code compiles. E. If lines 1, 3, and 5 are removed the code compiles.

package testing; public class SimpleClone implements Cloneable { int number = 100; int[] intArray = new int[10]; public SimpleClone() { int number = 100; for (int i = 0; i < intArray.length; i++) { intArray[i] = number; number++; } } public static void main(String[] args) { SimpleClone testclone1 = new SimpleClone(); SimpleClone testclone2; try { testclone2 = (SimpleClone) testclone1.clone(); testclone1.intArray[0] = 1200; testclone2.intArray[0] = 1400; testclone1.number = 1200; System.out.print(" testclone1 intArray[0] = " + testclone1.intArray[0]); System.out.print(" testclone1one2 intArray[0] = " + testclone2.intArray[0]); System.out.print(" testclone1 value of number = " + testclone1.number); System.out.print(" testclone2 value of number = " + testclone2.number); } catch (CloneNotSupportedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
technology programming languages

  1. testclone1 intArray[0] = 1400 testclone1one2 intArray[0] = 1400 testclone1 value of number = 1200 testclone2 value of number = 100

  2. testclone1 intArray[0] = 1200 testclone1one2 intArray[0] = 1400 testclone1 value of number = 1200 testclone2 value of number = 100

  3. testclone1 intArray[0] = 1400 testclone1one2 intArray[0] = 1400 testclone1 value of number = 1200 testclone2 value of number = 1200

  4. Compiler Error

Show answer
Correct Option: A

package io; import java.io.*; public class TestFile { public static void main(String[] args) { File file = new File("test_file.txt"); System.out.print(" Fle Name = " + file.getName()); file.delete(); file.renameTo(new File("test_file2.txt")); System.out.print(" Fle Name = " + file.getName()); } }
technology programming languages

  1. Null pointer Exception

  2. Fle Name = test_file.txt Fle Name = test_file.txt

  3. Compiler Error

  4. Fle Name = test_file.txt Fle Name = test_file2.txt

Show answer
Correct Option: B

package io; import java.io.*; public class TestFile1 { public static void main(String[] args) { //No file exists by the name test_file.txt File file = new File("test_file.txt"); System.out.print(" Fle Name = "+file.getName()); System.out.print(" File Status = "+file.exists()); } }
technology programming languages

  1. Fle Name = test_file.txt File Status = false

  2. Compiler Error

  3. Null Pointer Exception

  4. Fle Name = test_file.txt File Status = true

Show answer
Correct Option: A

package inheritance; interface test_Int { void test(); } abstract class IntImplementer implements test_Int { public static void main(String[] args) { System.out.println("Hello World!"); } }
technology programming languages

  1. No output

  2. Hello World!

  3. Compiler Error

  4. Exception

Show answer
Correct Option: B

package inheritance; class X { Y b = new Y(); X() { System.out.print("X"); } } class Y { Y() { System.out.print("Y"); } } public class Z extends X { Y y = new Y(); Z() { System.out.print("Z"); } public static void main(String[] args) { new Z(); } }
technology programming languages

  1. YXYZ

  2. Z

  3. ZX

  4. ZXYY

Show answer
Correct Option: A

Signature has to be the same for overloading.
technology programming languages

  1. True

  2. False

Show answer
Correct Option: B

Overriding is an example of runtime polymorphism.
technology programming languages

  1. True

  2. False

Show answer
Correct Option: A