How do I check an object's type in Java when it extends a common superclass?

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The simplest and most common way to check an object’s type in Java is using the instanceof operator. It allows you to determine whether an object is an instance of a specific class or its subclass.

Example Usage:

if (obj instanceof B) {
    System.out.println("Object is an instance of B");
} else if (obj instanceof C) {
    System.out.println("Object is an instance of C");
} else {
    System.out.println("Object is not an instance of B or C");
}

Why use instanceof?

  • It works at runtime and correctly identifies subclasses.
  • It prevents ClassCastException, unlike direct casting.
  • It is straightforward and widely used.