--- old/src/jdk.compiler/share/classes/com/sun/source/util/DocTrees.java	2020-07-23 09:48:40.109941910 -0700
+++ new/src/jdk.compiler/share/classes/com/sun/source/util/DocTrees.java	2020-07-23 09:48:39.682155894 -0700
@@ -47,6 +47,11 @@
  */
 public abstract class DocTrees extends Trees {
     /**
+     * Constructor for subclasses to call.
+     */
+    public DocTrees() {}
+
+    /**
      * Returns a DocTrees object for a given CompilationTask.
      * @param task the compilation task for which to get the Trees object
      * @return the DocTrees object