diff --git a/core/src/main/java/hudson/WebAppMain.java b/core/src/main/java/hudson/WebAppMain.java
index fbb3fcccdbfa6d72aaf01cf652580844e817f658..c47b1de1a2fa0db1ba081b34ce78037bbb3aa6dc 100644
--- a/core/src/main/java/hudson/WebAppMain.java
+++ b/core/src/main/java/hudson/WebAppMain.java
@@ -45,7 +45,7 @@ import java.util.logging.Logger;
  *
  * @author Kohsuke Kawaguchi
  */
-public class WebAppMain implements ServletContextListener {
+public final class WebAppMain implements ServletContextListener {
     private final RingBufferLogHandler handler = new RingBufferLogHandler();
     private static final String APP = "app";