Polish gh-1798

- Should throw IllegalStateException

Author: eleftherias

spring-session-core/src/main/java/org/springframework/session/web/http/SessionRepositoryFilter.java

@@ -312,7 +312,7 @@ public HttpSessionWrapper getSession(boolean create) {
 			}
 			if (SessionRepositoryFilter.this.httpSessionIdResolver instanceof CookieHttpSessionIdResolver
 					&& this.response.isCommitted()) {
-				throw new IllegalArgumentException("Cannot create a session after the response has been committed");
+				throw new IllegalStateException("Cannot create a session after the response has been committed");
 			}
 			if (SESSION_LOGGER.isDebugEnabled()) {
 				SESSION_LOGGER.debug(

spring-session-core/src/test/java/org/springframework/session/web/http/SessionRepositoryFilterTests.java

@@ -62,6 +62,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
@@ -425,7 +426,7 @@ public void doFilter(HttpServletRequest wrappedRequest) {
 
 	@Test
 	void doFilterGetSessionNewWhenResponseCommittedThenException() {
-		assertThatIllegalArgumentException().isThrownBy(() -> doFilter(new DoInFilter() {
+		assertThatIllegalStateException().isThrownBy(() -> doFilter(new DoInFilter() {
 			@Override
 			public void doFilter(HttpServletRequest wrappedRequest, HttpServletResponse wrappedResponse)
 					throws IOException {