Need to escape formatting character.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@5060 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/java/com/tigervnc/vncviewer/CConn.java b/java/com/tigervnc/vncviewer/CConn.java
index 3638463..09fa2d7 100644
--- a/java/com/tigervnc/vncviewer/CConn.java
+++ b/java/com/tigervnc/vncviewer/CConn.java
@@ -1166,8 +1166,8 @@
     key = ev.getKeyChar();
     location = ev.getKeyLocation();
 
-    String fmt = ev.paramString().replaceAll(",","%n       ");
-    vlog.debug(String.format(fmt));
+    String fmt = ev.paramString().replaceAll("%","%%");
+    vlog.debug(String.format(fmt.replaceAll(",","%n       ")));
 
     if (!ev.isActionKey()) {
       if (keycode >= KeyEvent.VK_0 && keycode <= KeyEvent.VK_9 &&