Adding User to keycloak and assigining a role

KeycloakAdminService.java

//took me 4 weeks to figure that out due to some pretty bad documentation on the interwebs
//hope this helps you folks

@Component
public class KeycloakAdminService {

    Logger logger = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);

    @Value("${keycloak.auth-server-url}")
    private String serverUrl;

    @Value("${keycloak.realm}")
    private String realm;

    @Value("${keycloak.resource}")
    private String clientId;

    @Value("${admin-user}")
    private String adminUsername;

    @Value("${admin-password}")
    private String adminPassword;

    @Value("${keycloak.credentials.secret}")
    private String secret;

    private final Map<String, List<String>> roleMapping = new HashMap<>();

    public UserRepresentation createKeycloakUser(AppUser appUser) {
        if (appUser instanceof Student) {
            this.roleMapping.put(this.clientId, appUser.getKeycloakRoleAsList());
        } else if (appUser instanceof Teacher) {
            this.roleMapping.put(this.clientId, appUser.getKeycloakRoleAsList());
        } else {
            this.roleMapping.put(this.clientId, Collections.singletonList(""));
        }
        Keycloak adminKeycloak = getAdminKeycloak();
        CredentialRepresentation cr = new CredentialRepresentation();
        cr.setType(OAuth2Constants.PASSWORD);
        cr.setValue(appUser.getPassword());

        UserRepresentation userRepresentation = new UserRepresentation();
        userRepresentation.setUsername(appUser.getUsername());
        userRepresentation.setClientRoles(roleMapping);
        userRepresentation.setCredentials(Collections.singletonList(cr));
        userRepresentation.setEnabled(true);

        adminKeycloak.realm(realm).users().create(userRepresentation);
        List<UserRepresentation> userList = adminKeycloak.realm(realm).users().search(appUser.getUsername()).stream()
                .filter(userRep -> userRep.getUsername().equals(appUser.getUsername())).collect(Collectors.toList());
        userRepresentation = userList.get(0);
        logger.info("User with id: " + userRepresentation.getId() + " created");


        this.assignRoleToUser(userRepresentation.getId(), appUser.getKeycloakRoleAsList().get(0));

        return userRepresentation;
    }

    private void assignRoleToUser(String userId, String role) {
        Keycloak keycloak = getAdminKeycloak();
        UsersResource usersResource = keycloak.realm(realm).users();
        UserResource userResource = usersResource.get(userId);

        //getting client
        ClientRepresentation clientRepresentation = keycloak.realm(realm).clients().findAll().stream().filter(client -> client.getClientId().equals(clientId)).collect(Collectors.toList()).get(0);
        ClientResource clientResource = keycloak.realm(realm).clients().get(clientRepresentation.getId());
        //getting role
        RoleRepresentation roleRepresentation = clientResource.roles().list().stream().filter(element -> element.getName().equals(role)).collect(Collectors.toList()).get(0);
        //assigning to user
        userResource.roles().clientLevel(clientRepresentation.getId()).add(Collections.singletonList(roleRepresentation));
    }

    private Keycloak getAdminKeycloak() {
        return KeycloakBuilder.builder().serverUrl(serverUrl)
                .realm(realm)
                .clientId(clientId)
                .username(adminUsername)
                .password(adminPassword)
                .grantType("password")
                .clientSecret(secret)
                .resteasyClient(
                        new ResteasyClientBuilder()
                                .connectionPoolSize(10).build()
                ).build();
    }

    public void deleteKeycloakUser(Student student) {
        Keycloak keycloak = getAdminKeycloak();
        List<UserRepresentation> userList = keycloak.realm(realm).users().search(student.getUsername());
        for (UserRepresentation user : userList) {
            if (user.getUsername().equals(student.getUsername())) {
                keycloak.realm(realm).users().delete(user.getId());
            }
        }
    }

}

Can you show your pom.xml?

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>de.magister</groupId>
    <artifactId>waterloo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>waterloo</name>
    <description>Magister Media waterloo Service</description>

    <properties>
        <java.version>11</java.version>
        <keycloak.version>10.0.2</keycloak.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.keycloak.bom</groupId>
                <artifactId>keycloak-adapter-bom</artifactId>
                <version>${keycloak.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.keycloak</groupId>
            <artifactId>keycloak-spring-boot-starter</artifactId>
            <version>${keycloak.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mariadb.jdbc</groupId>
            <artifactId>mariadb-java-client</artifactId>
            <version>2.6.1</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>3.4.4</version>
        </dependency>
    </dependencies>

    <packaging>jar</packaging>
    <build>
        <finalName>waterloo</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>