Tweaked logging around servlet container and added warning about jetty

Signed-off-by: Andrew DeMaria <lostonamountain@gmail.com>

airsonic-main/src/main/java/org/airsonic/player/Application.java

@@ -189,6 +189,7 @@ public class Application extends SpringBootServletInitializer implements Embedde
 
     @Override
     public void customize(ConfigurableEmbeddedServletContainer container) {
+        LOG.trace("Servlet container is {}", container.getClass().getCanonicalName());
         // Yes, there is a good reason we do this.
         // We cannot count on the tomcat classes being on the classpath which will
         // happen if the war is deployed to another app server like Jetty. So, we
@@ -197,6 +198,7 @@ public class Application extends SpringBootServletInitializer implements Embedde
         try {
             Class<?> tomcatESCF = Class.forName("org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory");
             if(tomcatESCF.isInstance(container)) {
+                LOG.info("Detected Tomcat web server");
                 LOG.debug("Attempting to optimize tomcat");
                 Object tomcatESCFInstance = tomcatESCF.cast(container);
                 Class<?> tomcatApplicationClass = Class.forName("org.airsonic.player.TomcatApplication");
@@ -207,10 +209,19 @@ public class Application extends SpringBootServletInitializer implements Embedde
                 LOG.debug("Skipping tomcat optimization as we are not running on tomcat");
             }
         } catch (NoClassDefFoundError | ClassNotFoundException e) {
-            LOG.debug("Skipping tomcat optimization as the tomcat classes are not available");
+            LOG.debug("No tomcat classes found");
         } catch (Exception e) {
             LOG.warn("An error happened while trying to optimize tomcat", e);
         }
+
+        try {
+            Class<?> jettyESCF = Class.forName("org.springframework.boot.context.embedded.jetty.JettyEmbeddedServletContainerFactory");
+            if(jettyESCF.isInstance(container)) {
+                LOG.warn("Detected Jetty web server. Here there be dragons.");
+            }
+        } catch (NoClassDefFoundError | ClassNotFoundException e) {
+            LOG.debug("No jetty classes found");
+        }
     }
 
     public static void main(String[] args) {