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Module 7: Advanced Object-Oriented Concepts

Lesson focus

Marker Interfaces & Metadata Alternatives

Understand historical marker interfaces and modern annotation-based replacements.

Marker interfaces like Serializable and Cloneable historically signaled runtime behavior via instanceof checks.

Annotations or explicit configuration often provide clearer metadata while avoiding type hierarchy pollution.

When maintaining legacy systems, document marker semantics so new developers know what behaviors they trigger.

Lesson quiz

What modern feature often replaces marker interfaces?

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