No, a class cannot extend itself in Java. If a class attempts to inherit from itself, the compiler will generate an error because it creates a circular inheritance relationship. Java inheritance requires a clear parent-child hierarchy, and self-inheritance would lead to an infinite inheritance loop.
Key Points: • A class cannot be both the parent and child of itself. • Self-inheritance creates a cyclic dependency, which is not allowed in Java. • The Java compiler detects such circular inheritance and throws a compilation error. • Inheritance must establish a valid "is-a" relationship between two different classes. • This restriction helps maintain a proper class hierarchy and prevents infinite recursion.
Example: If a class Employee tries to extend Employee, Java cannot determine a valid inheritance chain because the class would depend on itself indefinitely.
Code Example:
class Employee extends Employee {
}Compilation Error:
cyclic inheritance involving Employee
Valid Inheritance Example:
class Person {
void display() {
System.out.println("Person Details");
}
}
class Employee extends Person {
}In this case, Employee successfully inherits from Person because they are separate classes with a valid parent-child relationship.
Interview Tip: A concise interview answer is:
"No, a class cannot extend itself in Java. Doing so creates circular inheritance, which results in a compilation error because Java requires a valid and non-cyclic inheritance hierarchy."