修复问题

pattern-mediator/src/main/java/org/panda/App.java

@@ -0,0 +1,13 @@
+package org.panda;
+
+/**
+ * Hello world!
+ *
+ */
+public class App 
+{
+    public static void main( String[] args )
+    {
+        System.out.println( "Hello World!" );
+    }
+}