simplify main class

Signed-off-by: neo <1100909+neowu@users.noreply.github.com>

Author: neowu

ext/monitor/src/main/java/Main.java

@@ -3,8 +3,6 @@
 /**
  * @author ericchung
  */
-public class Main {
-    static void main() {
-        new MonitorApp().start();
-    }
+void main() {
+    new MonitorApp().start();
 }