IEEE Tech Event Contest

1. A class cannot be declared ......

Public

Private

Default

The keyword "private" in Java is used to restrict access to the class members (variables and methods) to only within the same class. It means that these members cannot be accessed from outside the class, including subclasses and other classes in the same package. Therefore, declaring a class as "private" would not make sense because it would prevent any other class from accessing it, resulting in limited or no usability.

Explanation

The keyword "private" in Java is used to restrict access to the class members (variables and methods) to only within the same class. It means that these members cannot be accessed from outside the class, including subclasses and other classes in the same package. Therefore, declaring a class as "private" would not make sense because it would prevent any other class from accessing it, resulting in limited or no usability.

2. Following code will result in: class A { public static void main(String [] args) { B b = new A(); } } class B extends A {}

Compile Error

Runtime Error

No Error

The given code will result in a compile error. This is because the line "B b = new A();" is trying to create an object of class A and assign it to a variable of class B. Since class B is a subclass of class A, this is not allowed in Java. The object being created must be of the same type as the variable it is being assigned to, or a subclass of that type. Therefore, the code will not compile.

Explanation

The given code will result in a compile error. This is because the line "B b = new A();" is trying to create an object of class A and assign it to a variable of class B. Since class B is a subclass of class A, this is not allowed in Java. The object being created must be of the same type as the variable it is being assigned to, or a subclass of that type. Therefore, the code will not compile.

3. Following code will result in: int a = 3.5;

Compilation error

Runtime error

A will equal 3.5

A will equal 3

The given code will result in a compilation error because the variable "a" is declared as an integer, but it is being assigned a floating-point value (3.5). In Java, you cannot directly assign a floating-point value to an integer variable without explicit casting. Therefore, the code will not compile.

Explanation

The given code will result in a compilation error because the variable "a" is declared as an integer, but it is being assigned a floating-point value (3.5). In Java, you cannot directly assign a floating-point value to an integer variable without explicit casting. Therefore, the code will not compile.

4. What is the size of a Char in Java?

1 bit

4 bit

8 bit

16 bit

In Java, the size of a Char is 16 bits. This means that a Char data type can store Unicode characters ranging from U+0000 to U+FFFF. Unicode characters are represented using the UTF-16 encoding, which requires 16 bits of storage for each character. Therefore, the correct answer is 16 bit.

Explanation

In Java, the size of a Char is 16 bits. This means that a Char data type can store Unicode characters ranging from U+0000 to U+FFFF. Unicode characters are represented using the UTF-16 encoding, which requires 16 bits of storage for each character. Therefore, the correct answer is 16 bit.

5. A class can be transient

True

False

A class cannot be transient. The transient keyword in programming is used to indicate that a variable should not be serialized, meaning it will not be saved and restored when the object is persisted or transferred. However, the transient keyword cannot be applied to a class itself. It can only be used to mark individual variables within a class as transient. Therefore, the statement "A class can be transient" is false.

Explanation

A class cannot be transient. The transient keyword in programming is used to indicate that a variable should not be serialized, meaning it will not be saved and restored when the object is persisted or transferred. However, the transient keyword cannot be applied to a class itself. It can only be used to mark individual variables within a class as transient. Therefore, the statement "A class can be transient" is false.

6. Following code will result in: int a = 9/0;

Compilation error: Divisions must be in a try block.

Compilation error: DivideByZeroException

Runtime Exception

No Error: a is Null

The code will result in a runtime exception because it is trying to divide 9 by 0, which is not allowed in mathematics. This will throw a runtime exception called "ArithmeticException" or "DivideByZeroException" in most programming languages.

Explanation

The code will result in a runtime exception because it is trying to divide 9 by 0, which is not allowed in mathematics. This will throw a runtime exception called "ArithmeticException" or "DivideByZeroException" in most programming languages.