Restore Java 1.6 compatibility

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -864,7 +864,7 @@ public class ServerProperties
 					.getIncludeStacktrace() == ErrorProperties.IncludeStacktrace.NEVER) {
 				customizeErrorReportValve(factory);
 			}
-			Cookie cookie = serverProperties.getSession().getCookie();
+			final Cookie cookie = serverProperties.getSession().getCookie();
 			if (cookie.getHttpOnly() != null) {
 				factory.addContextCustomizers(new TomcatContextCustomizer() {
 

spring-boot/src/main/java/org/springframework/boot/web/support/ErrorPageFilter.java

@@ -84,7 +84,7 @@ public class ErrorPageFilter implements Filter, ErrorPageRegistry {
 
 	private static final Set<Class<?>> CLIENT_ABORT_EXCEPTIONS;
 	static {
-		Set<Class<?>> clientAbortExceptions = new HashSet<>();
+		Set<Class<?>> clientAbortExceptions = new HashSet<Class<?>>();
 		addClassIfPresent(clientAbortExceptions,
 				"org.apache.catalina.connector.ClientAbortException");
 		CLIENT_ABORT_EXCEPTIONS = Collections.unmodifiableSet(clientAbortExceptions);