how to write unit tests for these class?

Slf4j @Service public class JwtTokenServiceImpl implements JwtTokenService { @Value("${okta.clientServiceAppSecret}") private String clientSecret; @Value("${okta.oktaServer}") private String oktaServer; @Value("${pdrm.jwt.pdrmServiceClaim}") private String pdrmServiceClaim; private JwtTokenGetterClient jwtTokenGetterClient; @Autowired public void setJwtTokenGetterClient(JwtTokenGetterClient jwtTokenGetterClient) { this.jwtTokenGetterClient = jwtTokenGetterClient; } @Override public TokenEntity getToken() { Map queryMap = Map.of("client_id", pdrmServiceClaim, "client_secret", clientSecret, "grant_type", "client_credentials", "scope", "default"); //get a token return jwtTokenGetterClient.getToken(oktaServer, queryMap); } } 

public class FeignConfiguration { @Bean Logger.Level feignLoggerLevel() { return Logger.Level.FULL; } @Bean public FeignErrorDecoder pdrmErrorDecoder() { return new FeignErrorDecoder(); } @Autowired private ObjectFactory messageConverters; @Bean @Primary @Scope(SCOPE_PROTOTYPE) Encoder feignFormEncoder() { return new FormEncoder(new SpringEncoder(this.messageConverters)); } } 

@Slf4j public class FeignErrorDecoder implements ErrorDecoder { private final ErrorDecoder defaultErrorDecoder = new Default(); private static final Logger LOGGER = LoggerFactory.getLogger(WebClientUtils.class); @Override public Exception decode(String methodKey, Response response) { if (response.status() >= 300 && response.status() <= 399) { LOGGER.debug("Feign got a redirection response of {}", response.status()); LOGGER.debug("Feign response: {}", response); } if (response.status() >= 400 && response.status() <= 499) { LOGGER.debug("Feign got a client error response of {}", response.status()); LOGGER.debug("Feign got a client error methodKey {}", methodKey); LOGGER.debug("Feign response: {}", response); LOGGER.debug("Request: " + response.request()); LOGGER.debug("Request URL: " + response.request().url()); } if (response.status() >= 500 && response.status() <= 599) { LOGGER.debug("Feign got a system error response of {}", response.status()); LOGGER.debug("Feign response: {}", response); } return defaultErrorDecoder.decode(methodKey, response); } } 

@Slf4j @Component public class ValidateImpl implements Validate { private final PerformanceUtils perf = new PerformanceUtils(false); private final ServiceCalls serviceCalls; @Autowired public ValidateImpl(ServiceCalls serviceCalls) { this.serviceCalls = serviceCalls; // if (logger.isDebugEnabled()) { // perf.enabled(true); // } } /** * {@inheritDoc} */ public ValidateEntity get(String ruleName, String operation) { return serviceCalls.getValidate(ruleName, operation); } }