Refactor this method to not always return the same value

[H.Lo (Hrvoje Lončar)]

Warning message: Methods returns should not be invariant (java:S3516)

The warning is attached to method preHandle()

OS: Windows 10 Pro; Version 21H2; OS build 19044.1348; Windows Feature Experience Pack 120.2212.3920.0
Java: Java version “17” 2021-09-14 LTS; Java™ SE Runtime Environment (build 17+35-LTS-2724)
Project Java compliance: Java 11
IDE: Spring Tool Suite 4; Version: 4.12.1.RELEASE; Build Id: 202110260750
SonarLint: SonarLint (for Eclipse) v7.1.0.39158

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Configuration
public class CustomWebMvcConfigurer implements WebMvcConfigurer {

	public static final String CUSTOM_FORCED_LOCALE = "CUSTOM_FORCED_LOCALE";

	public class CustomLocaleChangeInterceptor extends LocaleChangeInterceptor {

		@Override
		protected Locale parseLocaleValue(final String localeValue) {
			return super.parseLocaleValue(localeValue);
		}

		/**
		 * I get warning message here on method name
		 */
		@Override
		public boolean preHandle(
			final HttpServletRequest request, 
			final HttpServletResponse response, 
			final Object handler
		) throws ServletException {
			final String newLocale = request.getParameter(getParamName());
			if (newLocale == null) {
				// proceed
				return true;
			}
			if (!customCheckHttpMethod(request.getMethod())) {
				// proceed
				return true;
			}
			final LocaleResolver localeResolver = 
				RequestContextUtils.getLocaleResolver(request);
			if (localeResolver == null) {
				throw new IllegalStateException(
					"No Resolver found: not in a DispatcherServlet request?"
				);
			}
			try {
				final Locale parsedLocale = parseLocaleValue(newLocale);
				request.setAttribute(CUSTOM_FORCED_LOCALE, newLocale);
				localeResolver.setLocale(request, response, parsedLocale);
			}
			catch (final IllegalArgumentException e) {
				if (!isIgnoreInvalidLocale()) {
					throw e;
				}
			}
			// proceed
			return true;
		}
	
		private boolean customCheckHttpMethod(final String method) {
			final String[] configuredMethods = getHttpMethods();
			if (ObjectUtils.isEmpty(configuredMethods)) {
				return true;
			}
			for (final String configuredMethod : configuredMethods) {
				if (configuredMethod.equalsIgnoreCase(method)) {
					return true;
				}
			}
			return false;
		}

	}

}

[Richard_Mathis]

Hi Hrvoje Loncar,

Thank you for your message.

I agree with you that your example generates a false-positive. This rule might currently unfortunately raise a few false-positive. Going further in the reduction of false-positive (target 0) is in our objectives but no date can be committed.

Regards,
Richard