--- old/src/java.base/share/classes/java/net/URLDecoder.java	2020-07-23 17:23:21.703597194 -0700
+++ new/src/java.base/share/classes/java/net/URLDecoder.java	2020-07-23 17:23:21.315597194 -0700
@@ -81,6 +81,12 @@
 
 public class URLDecoder {
 
+    /**
+     * Do not call.
+     */
+    @Deprecated(since="16", forRemoval=true)
+    public URLDecoder() {}
+
     // The platform default encoding
     static String dfltEncName = URLEncoder.dfltEncName;