Be defensive about classloader in MessageSourceAutoConfiguration

Fixes gh-1960

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/MessageSourceAutoConfiguration.java

@@ -137,7 +137,7 @@ public class MessageSourceAutoConfiguration {
 				return new SkipPatternPathMatchingResourcePatternResolver(classLoader)
 						.getResources("classpath*:" + name + "*.properties");
 			}
-			catch (IOException ex) {
+			catch (Exception ex) {
 				return NO_RESOURCES;
 			}
 		}
@@ -153,10 +153,15 @@ public class MessageSourceAutoConfiguration {
 
 		private static final ClassLoader ROOT_CLASSLOADER;
 		static {
-			ClassLoader classLoader = ClassLoader.getSystemClassLoader();
+			ClassLoader classLoader = null;
+			try {
+				classLoader = ClassLoader.getSystemClassLoader();
 				while (classLoader.getParent() != null) {
 					classLoader = classLoader.getParent();
 				}
+			}
+			catch (Throwable e) {
+			}
 			ROOT_CLASSLOADER = classLoader;
 		}