Object lifecycle

An object goes through several stages from creation to destruction.

1. Declaration – reference variable is created on the stack (no object yet).

Person p;  // reference variable, null

2. Instantiation – memory is allocated on the heap using new.

p = new Person();  // object created

3. Initialization – constructor runs, fields are initialized.

4. Usage – object is used via its reference.

p.setName("Alice");
String name = p.getName();

5. Becoming unreachable – when no references point to the object.

p = null;        // object becomes unreachable
// or method exits, local reference goes out of scope

6. Garbage collection – JVM automatically frees memory (nondeterministic time).

7. Finalization (deprecated) – historically, finalize() was called before collection. Now discouraged.

8. Memory reclamation – memory is returned to the heap for reuse.

Diagram

Declaration → Instantiation → Initialization → Usage → Unreachable → GC → Reclamation

Best practices:

• Minimize object creation in performance‑critical loops.
• Use object pooling for expensive objects.
• Let GC handle memory; avoid manual interference.
• Use try‑with‑resources for external resources.