Using Spring Boot and Java to create a complete REST API. I am using PostgreSQL as the relational database and Spring JdbcTemplate for interacting with that. Apart from this, I am adding authentication using JWT (JSON Web Tokens).
CRUD OPERATIONS
@RequestMapping("/api/users")
- @PostMapping("/login")
 - @PostMapping("/register")
 
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@RequestMapping("/api/categories")
 - 
@GetMapping("")
 - 
@GetMapping("/{categoryId}")
 - 
@PostMapping("")
 - 
@PutMapping("/{categoryId}")
 - 
@DeleteMapping("/{categoryId}")
 
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@RequestMapping("/api/categories/{categoryId}/transactions")
 - 
@GetMapping("")
 - 
@GetMapping("{transactionId}")
 - 
@PostMapping("")
 - 
@PutMapping("/{transactionId}")
 - 
@DeleteMapping("/{transactionId}")