Mastering OOP Concepts in Java

What is the scope of a variable declared inside a method?

• Static scope that persists after the method ends.

• Global scope accessible throughout the program.

• Local scope within the method.

• Block scope limited to the enclosing block.

Which of the following is a primitive data type in Java?

• float

• string

• boolean

• int

What is the purpose of a class constructor in Java?

• To store data for the class.

• The purpose of a class constructor in Java is to initialize objects of the class.

• To create static variables for the class.

• To define methods for the class.

How do you instantiate an object of a class in Java?

• ClassName obj = ClassName();

• ClassName newObj = ClassName;

• new ClassName obj = new();

• ClassName obj = new ClassName();

What is method overloading and how is it achieved in Java?

• Method overloading is achieved by defining multiple methods with the same name but different parameter types or counts in Java.

• Method overloading requires the methods to have the same number of parameters only.

• Method overloading is achieved by using different method names in Java.

• Method overloading is a feature that allows methods to be defined with the same name and return type only.

What is the operator precedence of the '+' operator compared to the '*' operator?

• The '+' and '*' operators have equal precedence.

• The '*' operator has the lowest precedence among all operators.

• The '*' operator has higher precedence than the '+' operator.

• The '+' operator has higher precedence than the '*' operator.

What is the difference between instance variables and local variables?

• Instance variables are defined inside methods; local variables are defined outside methods.

• Instance variables are tied to an object; local variables are tied to a method.

• Local variables can be accessed by all objects; instance variables cannot.

• Instance variables are temporary; local variables are permanent.

Which data type would you use to store a single character in Java?

• char

• int

• boolean

• String

How can you call a constructor from another constructor in the same class?

• Call the constructor directly without parameters.

• Use 'new ConstructorName(parameters);' to invoke another constructor.

• Use 'super(parameters);' to call another constructor.

• Use 'this(parameters);' to call another constructor.

What happens if you do not provide a constructor in a Java class?

• A default no-argument constructor is provided by the compiler.

• The compiler throws an error if no constructor is provided.

• The class cannot be instantiated without a constructor.

• A constructor must always be explicitly defined.