<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-admin-client</artifactId>
    <version>1.8.0.CR3</version>
</dependency>

public User save(User user) {
    Keycloak kc = Keycloak.getInstance("http://localhost:8080/auth", "forum", “admin", “admin", "security-admin-console");

    CredentialRepresentation credential = new CredentialRepresentation();
    credential.setType(CredentialRepresentation.PASSWORD);
    credential.setValue(user.getPassword());
    UserRepresentation newUser = new UserRepresentation();
    newUser.setUsername(user.getLogin());
    newUser.setFirstName(user.getName());
    newUser.setCredentials(Arrays.asList(credential));

    kc.realm("forum").users().create(newUser);

    User saved = repository.save(user);
    savedUser.fire(saved);
    return saved;
}