Allow META-INF/resources in WAR classes folder

Update `TomcatResources` so that `META-INF/resources` folders in
`src/main/resources` no longer fail with a "URI is not hierarchical"
exception.

Closes gh-13265

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatResources.java

@@ -59,6 +59,9 @@ abstract class TomcatResources {
 					}
 					addJar(jar);
 				}
+				else if ("jar".equals(url.getProtocol())) {
+					addJar(url.toString());
+				}
 				else {
 					addDir(new File(url.toURI()).getAbsolutePath(), url);
 				}

spring-boot/src/test/java/org/springframework/boot/context/embedded/tomcat/TomcatResourcesTests.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.context.embedded.tomcat;
+
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.catalina.Context;
+import org.junit.Test;
+
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link TomcatResources}.
+ *
+ * @author Phillip Webb
+ */
+public class TomcatResourcesTests {
+
+	@Test
+	public void nonHierarchicalUri() throws Exception {
+		// gh-13265
+		Context context = mock(Context.class);
+		TomcatResources resources = new TomcatResources.Tomcat8Resources(context);
+		List<URL> resourceJarUrls = new ArrayList<URL>();
+		resourceJarUrls.add(new URL("jar:file:/opt/app/app.war!/WEB-INF/classes!/"));
+		resources.addResourceJars(resourceJarUrls);
+	}
+
+}