Throw IllegalArgumentException instead of RuntimeException on bad input
to FtpServerListener
diff --git a/examples/ftpserver-example-spring-war/src/main/java/org/apache/ftpserver/example/springwar/FtpServerListener.java b/examples/ftpserver-example-spring-war/src/main/java/org/apache/ftpserver/example/springwar/FtpServerListener.java
index c42782e..315ff38 100644
--- a/examples/ftpserver-example-spring-war/src/main/java/org/apache/ftpserver/example/springwar/FtpServerListener.java
+++ b/examples/ftpserver-example-spring-war/src/main/java/org/apache/ftpserver/example/springwar/FtpServerListener.java
@@ -70,7 +70,7 @@
             server.start();
             System.out.println("FtpServer started");
         } catch (Exception e) {
-            throw new RuntimeException("Failed to start FtpServer", e);
+            throw new IllegalArgumentException("Failed to start FtpServer", e);
         }
     }
 }