Generate UUID in Java
Use the built-in java.util.UUID class — available since Java 1.5, no dependencies needed. Includes Spring Boot JPA and REST patterns.
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Open UUID v4 Generator →The Quick Answer
Java's standard library includes java.util.UUID since Java 1.5. No Maven or Gradle dependency needed.
import java.util.UUID;
UUID id = UUID.randomUUID();
System.out.println(id.toString());
// → "f47ac10b-58cc-4372-a567-0e02b2c3d479"
// As a plain string
String idStr = UUID.randomUUID().toString();
// Without hyphens
String compact = idStr.replace("-", "");Spring Boot — JPA Entity with UUID Primary Key
import jakarta.persistence.*;
import java.util.UUID;
@Entity
@Table(name = "products")
public class Product {
@Id
@GeneratedValue(strategy = GenerationType.UUID) // Hibernate 6+ / Spring Boot 3+
private UUID id;
@Column(nullable = false)
private String name;
// Getters / setters ...
}import org.hibernate.annotations.GenericGenerator;
import javax.persistence.*;
import java.util.UUID;
@Entity
public class Product {
@Id
@GeneratedValue(generator = "uuid2")
@GenericGenerator(name = "uuid2", strategy = "uuid2")
@Column(columnDefinition = "BINARY(16)")
private UUID id;
}Spring Boot — REST Controller with UUID Path Variable
import org.springframework.web.bind.annotation.*;
import java.util.UUID;
@RestController
@RequestMapping("/api/products")
public class ProductController {
@GetMapping("/{id}")
public Product getProduct(@PathVariable UUID id) {
// Spring automatically parses and validates the UUID path variable
return productService.findById(id);
}
@PostMapping
public Product createProduct(@RequestBody CreateProductRequest req) {
// UUID generated by JPA @GeneratedValue
return productService.create(req);
}
}Name-Based UUIDs (v3 and v5)
import java.util.UUID;
// UUID v3 — MD5 hash of a name within a namespace
// Same inputs always produce the same UUID
UUID nameId = UUID.nameUUIDFromBytes("example.com".getBytes());
System.out.println(nameId);
// → "9073926b-929f-31c2-abc9-fad77ae3e8eb"
// Note: Java stdlib only has v3 (MD5). For v5 (SHA-1), use a library.Frequently Asked Questions
Do I need a dependency to generate UUIDs in Java?
No. java.util.UUID has been part of the Java standard library since Java 1.5. Just call UUID.randomUUID() — no Maven or Gradle dependency needed.
Is UUID.randomUUID() thread-safe in Java?
Yes. UUID.randomUUID() uses SecureRandom internally, which is thread-safe. You can call it from multiple threads concurrently without synchronization.
How do I use a UUID as a primary key in Spring Boot JPA?
Annotate the ID field with @Id and @GeneratedValue(strategy = GenerationType.UUID) (Spring Boot 3+ / Hibernate 6+), or use @GeneratedValue(generator = "uuid2") with the Hibernate UUIDGenerator for older versions. PostgreSQL, MySQL 8+, and H2 all support UUID column types natively.
Should I store UUIDs as VARCHAR or BINARY in MySQL?
Store as BINARY(16) for best performance. A BINARY(16) column uses 16 bytes versus 36 bytes for VARCHAR(36), and comparisons are faster. Use UUID_TO_BIN(uuid, 1) (the second argument reorders bytes for better index locality) and BIN_TO_UUID(bin, 1) to convert. In Hibernate, annotate with @Column(columnDefinition = "BINARY(16)").