HTTP Methods in REST APIs

HTTP methods define the action performed on a resource. Using the correct method is fundamental to RESTful API design and is tested in Java developer interviews worldwide.

Method Reference

GET

Retrieve resource(s). Safe and idempotent. Never modify data.

POST

Create new resource. Not idempotent — repeated calls may create duplicates.

PUT

Replace entire resource. Idempotent.

PATCH

Partial update. Idempotent when designed correctly.

DELETE

Remove resource. Idempotent.

Spring Boot Example

@RestController
@RequestMapping("/api/products")
public class ProductController {
    @GetMapping("/{id}")
    public Product get(@PathVariable Long id) { ... }

    @PostMapping
    public ResponseEntity<Product> create(@RequestBody Product p) { ... }

    @PutMapping("/{id}")
    public Product update(@PathVariable Long id, @RequestBody Product p) { ... }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> delete(@PathVariable Long id) { ... }
}

Frequently Asked Questions

POST vs PUT for updates?▼

Use PUT to replace the entire resource. Use PATCH for partial updates. POST is for creating new resources.