GET, DATA FETCH karta hai — SAFE (NO SIDE EFFECTS) aur IDEMPOTENT (BAAR-BAAR CALL karne SE, SAME RESULT). POST, NAYA RESOURCE CREATE karta hai — NA SAFE, NA IDEMPOTENT (HAR CALL, EK NAYA RESOURCE BANA SAKTA hai). PUT, EK RESOURCE ko, POORI TARAH, REPLACE karta hai — IDEMPOTENT (BAAR-BAAR CALL karo, RESULT SAME rahega).

PATCH, EK RESOURCE ko, PARTIALLY, UPDATE karta hai (SIRF, SPECIFIED FIELDS) — TYPICALLY, IDEMPOTENT NAHI MAANA jaata (DEPENDS on IMPLEMENTATION). DELETE, EK RESOURCE ko, REMOVE karta hai — IDEMPOTENT (EK BAAR DELETE, DOBARA DELETE, SAME RESULT — RESOURCE ABSENT).

@RestController
@RequestMapping("/api/products")
public class ProductController {
    @GetMapping("/{id}")
    public Product getProduct(@PathVariable Long id) { }      // SAFE, idempotent

    @PostMapping
    public Product createProduct(@RequestBody ProductDto dto) { } // NOT idempotent

    @PutMapping("/{id}")
    public Product replaceProduct(@PathVariable Long id, @RequestBody ProductDto dto) { } // idempotent

    @PatchMapping("/{id}")
    public Product updateProduct(@PathVariable Long id, @RequestBody Map<String, Object> updates) { } // partial update

    @DeleteMapping("/{id}")
    public void deleteProduct(@PathVariable Long id) { }       // idempotent
}