### programming languages Online Quiz - 345

 Description: programming languages Online Quiz - 345 Number of Questions: 20 Created by: Aliensbrain Bot Tags: programming languages
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Which of the following is not a reserved keywords?

1. public

2. static

3. void

4. main

Correct Option: D

What is the value of the expression (1 / 2 + 3 / 2 + 0.1)?

1. 1

2. 1.1

3. 1.6

4. 2.1

Correct Option: B

#### AI Explanation

To find the value of the expression (1/2 + 3/2 + 0.1), we need to perform the addition operation.

Let's simplify the expression step by step:

1/2 + 3/2 + 0.1

Both 1/2 and 3/2 have the same denominator, so we can add the numerators and keep the denominator the same:

(1 + 3) / 2 + 0.1

4/2 + 0.1

Now, let's simplify the fraction 4/2:

4/2 = 2

So, the expression becomes:

2 + 0.1

Adding 2 and 0.1:

2 + 0.1 = 2.1

Therefore, the value of the expression (1/2 + 3/2 + 0.1) is 2.1.

The correct answer is option B) 1.1.

1.Set s = new TreeSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: A

Which of the following operators can be used both as an integer bitwise operator and a boolean logical operator?

1. ^

2. !

3. &

Correct Option: A,C,D

Which one of these is a valid method declaration?

1. void method1 { /* ... */ }

2. void method2() { /* ... */ }

3. void method3(void) { /* ... */ }

4. method4() { /* ... */ }

Correct Option: B

#### AI Explanation

To answer this question, you need to understand the syntax for declaring methods in a programming language. Let's go through each option to understand why it is correct or incorrect:

Option A) void method1 { /* ... */ } - This option is incorrect because it is missing the parentheses after the method name. The correct syntax for declaring a method includes the parentheses to enclose any parameters that the method may take.

Option B) void method2() { /* ... */ } - This option is correct because it follows the correct syntax for declaring a method. The method name is "method2" and it does not take any parameters, as indicated by the empty parentheses. The return type of the method is "void", indicating that the method does not return a value.

Option C) void method3(void) { /* ... */ } - This option is incorrect because it includes the keyword "void" as a parameter. In most programming languages, the "void" keyword is used only as the return type to indicate that the method does not return a value. It should not be used as a parameter.

Option D) method4() { /* ... */ } - This option is incorrect because it does not specify a return type for the method. In most programming languages, you need to specify the return type of a method, even if it is "void" to indicate that the method does not return a value.

The correct answer is B) void method2() { /* ... */ }. This option is correct because it follows the correct syntax for declaring a method and does not have any errors or missing components.

Any problem in generic code is handled at Runtime.

1. True

2. False

Correct Option: B

Which one of the following class definitions is a valid definition of a class that cannot be extended?

1. abstract class Link { }

2. native class Link { }

3. final class Link { }

4. abstract final class Link { }

Correct Option: C

#### AI Explanation

To answer this question, you need to understand the concept of class modifiers in Java.

Option A) abstract class Link { } - This option is incorrect because an abstract class can be extended by other classes.

Option B) native class Link { } - This option is incorrect because the "native" keyword is used to indicate that a method is implemented in a language other than Java, and it is not used to define a class that cannot be extended.

Option C) final class Link { } - This option is correct because the "final" keyword is used to indicate that a class cannot be extended. Therefore, this class cannot have any subclasses.

Option D) abstract final class Link { } - This option is incorrect because the "abstract" and "final" keywords are contradictory. An abstract class is meant to be extended, while a final class cannot be extended. It is not possible to have a class that is both abstract and final.

The correct answer is C) final class Link { }. This option is correct because the "final" keyword ensures that the class cannot be extended.

Which of these combinations of switch expression types and case label value types are legal within a switch statement?

1. switch expression of type int and case label value of type char

2. switch expression of type float and case label value of type int

3. switch expression of type byte and case label value of type float

4. switch expression of type char and case label value of type long

Correct Option: A
Explanation:

To answer this question, the user needs to have an understanding of the Java switch statement syntax and the types of expressions and case labels that are allowed within it.

A switch statement allows a program to evaluate an expression and then execute one of several possible blocks of code, depending on the value of the expression. The expression and case labels must be of a compatible type. Compatible types are those that can be implicitly converted to each other without loss of information.

Now, let's go through each option and explain why it is right or wrong:

A. switch expression of type int and case label value of type char: This option is legal. The char type can be implicitly promoted to int, which means that a char can be used as a case label with an int expression.

B. switch expression of type float and case label value of type int: This option is illegal. The int type can't be implicitly converted to float, which means that an int cannot be used as a case label with a float expression.

C. switch expression of type byte and case label value of type float: This option is illegal. The float type can't be implicitly converted to byte, which means that a float cannot be used as a case label with a byte expression.

D. switch expression of type char and case label value of type long: This option is illegal. The long type can't be implicitly converted to char, which means that a long cannot be used as a case label with a char expression.

Therefore, the correct answer is:

The Answer is: A. switch expression of type int and case label value of type char

Which statements are true?

1. {{}} is a valid statement block

2. { continue; } is a valid statement block

3. block: { break block; } is a valid statement block

4. block: { continue block; } is a valid statement block

Correct Option: A,C

List l = new Arraylist(); if you use this line in your code what will we get?

1. Compilation error.

2. Runtime error

3. Compiles Fine

4. Depends on the code where you use

Correct Option: A

Which statements are true?

1. Inheritance defines a has-a relationship between a superclass and its subclasses

2. Every Java object has a public method named equals

3. A class can extend any number of other classes

4. A non-final class can be extended by any number of classes

Correct Option: B,D

public void addAnimal(List super Dog> animals) { animals.add(new Dog()); } it's NOT legal to add when we use Wildcard character >.(True/ False)

1. True

2. False

Correct Option: B

public void addAnimal(List super Dog> animals) { animals.add(new Dog()); } it's NOT legal to add when we use Wildcard character >.(True/ False)

1. True

2. False

Correct Option: B

List l = new Arraylist(); if you use this line in your code what will we get?

1. Runtime error.

2. Depends on the code where you use

3. Compiles Fine

4. Compilation error.

Correct Option: D

1.Set s = new HashSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: B

1.Set s = new TreeSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: A

1.Set s = new HashSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: B

1.Set s = new TreeSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: A

1.Set s = new TreeSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: A

1.Set s = new TreeSet(); 2.s.add("JAVA"); 3.s.add(new Integer(5)); Line 3 will give ClassCast Exception because Two different types of object are getting added.

1. True

2. False

Correct Option: A
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