Hibernate / JPA 2 / PostgreSQL - Entity UUID as a Primary Key

Question

I am trying to use a UUID as a primary key with Hibernate, and let PostgreSQL or Hibernate automatically generate those IDs. Ideally, I would also like to have java.util.UUID object that I can work with too.

To do this, I'm trying to map the java.util.UUID to the UUID data type in Postgres. I can get Hibernate to generate the database correctly, and put data into the entity's table. However, retrieving the data back via Spring, I get this:

Provided id of the wrong type for class com.example.somepackage.Brand. Expected: class java.util.UUID, got class java.lang.String; nested exception is java.lang.IllegalArgumentException: Provided id of the wrong type for class com.example.somepackage.Brand. Expected: class java.util.UUID, got class java.lang.String

Apologies if this is a simple fix; I'm very new to Spring/Hibernate. Some help would be greatly appreciated.

@Entity
public class Brand {

    @javax.persistence.Id
    @GenericGenerator(name = "uuid-gen", strategy = "uuid2")
    @GeneratedValue(generator = "uuid-gen")
    @org.hibernate.annotations.Type(type="pg-uuid")
    private UUID id;
    private String brand;

    public UUID getId() {
        return id;
    }

    public void setId(UUID id) {
        this.id = id;
    }

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }
}

Maven pom.xml is as follows

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0  http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>spring-rest-entity-test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-rest-entity-test</name>
    <description>Test</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.3.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <start-class>com.example.somepackage.Main</start-class>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-rest-core</artifactId>
            <version>2.3.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-commons</artifactId>
            <version>1.10.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-rest-webmvc</artifactId>
            <version>2.3.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.0-api</artifactId>
            <version>1.0.0.Final</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>9.1-901-1.jdbc4</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Answer 1

Solved it myself. Turns out I had forgotten to update the Repository class to use java.util.UUID and not String.

@RepositoryRestResource(collectionResourceRel = "brand", path = "brand")
public interface BrandRepo extends PagingAndSortingRepository<Brand, UUID> { // Was previously <Brand, String>
    List<Brand> findByBrand(@Param("brand") String brand);
}