Fixed toConnectionString() to avoid NPE.

jetty-io/src/main/java/org/eclipse/jetty/io/ssl/SslConnection.java

@@ -307,12 +307,13 @@ public class SslConnection extends AbstractConnection
         b = _decryptedInput;
         int di=b==null?-1:b.remaining();
 
+        Connection connection = _decryptedEndPoint.getConnection();
         return String.format("%s@%x{%s,eio=%d/%d,di=%d}=>%s",
                 getClass().getSimpleName(),
                 hashCode(),
                 _sslEngine.getHandshakeStatus(),
                 ei,eo,di,
-                ((AbstractConnection)_decryptedEndPoint.getConnection()).toConnectionString());
+                connection instanceof AbstractConnection ? ((AbstractConnection)connection).toConnectionString() : connection);
     }
 
     public class DecryptedEndPoint extends AbstractEndPoint