Keycloak kc = Keycloak.getInstance(
                "http://localhost:8180/auth",
                "master",
                "admin", "admin",
                "admin-cli");

CredentialRepresentation credential = new CredentialRepresentation();
credential.setType(CredentialRepresentation.PASSWORD);
credential.setValue("test123");
UserRepresentation user = new UserRepresentation();
user.setUsername("testuser");
user.setFirstName("Test");
user.setLastName("User");
user.setCredentials(Arrays.asList(credential));
kc.realm("test").users().create(user);