java 13 interview questions and answers

Abstract class must be subclassed and final class cannot be subclassed. In Java, an abstract class and a final class are two different concepts with distinct characteristics: Abstract Class: An abstract class is a class that cannot be instantiated on its own. It may contain both abstract (methods without a body) and concrete (methods with … Read more

If one or more methods of the class are abstract. If class inherits one or more abstract methods from the parent abstract class and no implementation is provided for that method If class implements an interface and provides no implementation for those methods. In Java, a class is marked as abstract when it contains one … Read more

No abstract class cannot be instantiated i.e you cannot create a new object of this class No, an abstract class cannot be instantiated in Java. An abstract class is a class that is declared with the abstract keyword. It may have abstract methods (methods without a body) that must be implemented by its subclasses. Abstract … Read more

: No it is applied only to class and methods No, the abstract modifier cannot be applied to a variable in Java. The abstract modifier is used with classes and methods, not with variables. In Java, you use the abstract keyword to declare abstract classes and methods. An abstract class is a class that cannot … Read more

No the reference cannot be change, but the data in that object can be changed. In Java, when a reference variable is declared as final, it means that the reference cannot be changed to point to a different object. However, the state of the object itself (i.e., the data within the object) can be modified … Read more