Summary

Add explicit constructors to API classes of javax.swing that have default constructors

Problem

Default constructors are not recommended for classes that are parts of a formal API.

Solution

Add explicit public no-arg constructors for public classes and protected no-arg constructor for public abstract classes.

Specification

--- old/src/java.desktop/share/classes/javax/swing/AbstractButton.java  2020-08-19 13:38:31.908720400 +0530
+++ new/src/java.desktop/share/classes/javax/swing/AbstractButton.java  2020-08-19 13:38:29.802996000 +0530
@@ -236,6 +236,11 @@
     private boolean hideActionText = false;

     /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractButton() {}
+
+    /**
      * Sets the <code>hideActionText</code> property, which determines
      * whether the button displays text from the <code>Action</code>.
      * This is useful only if an <code>Action</code> has been
--- old/src/java.desktop/share/classes/javax/swing/AbstractCellEditor.java  2020-08-19 13:38:44.644574500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/AbstractCellEditor.java  2020-08-19 13:38:42.417337900 +0530
@@ -62,6 +62,11 @@
      */
     protected transient ChangeEvent changeEvent = null;

+    /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractCellEditor() {}
+
     // Force this to be implemented.
     // public Object  getCellEditorValue()

--- old/src/java.desktop/share/classes/javax/swing/AbstractListModel.java   2020-08-19 13:38:57.183130600 +0530
+++ new/src/java.desktop/share/classes/javax/swing/AbstractListModel.java   2020-08-19 13:38:55.114290600 +0530
@@ -55,6 +55,10 @@
      */
     protected EventListenerList listenerList = new EventListenerList();

+    /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractListModel() {}

     /**
      * Adds a listener to the list that's notified each time a change
--- old/src/java.desktop/share/classes/javax/swing/AbstractSpinnerModel.java    2020-08-19 13:39:10.537865100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/AbstractSpinnerModel.java    2020-08-19 13:39:08.368045100 +0530
@@ -64,6 +64,10 @@
      */
     protected EventListenerList listenerList = new EventListenerList();

+    /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractSpinnerModel() {}

     /**
      * Adds a ChangeListener to the model's listener list.  The
--- old/src/java.desktop/share/classes/javax/swing/DefaultDesktopManager.java   2020-08-19 13:39:23.452744800 +0530
+++ new/src/java.desktop/share/classes/javax/swing/DefaultDesktopManager.java   2020-08-19 13:39:21.081096900 +0530
@@ -76,6 +76,11 @@
      */
     private transient boolean didDrag;

+    /**
+     * Constructs a {@code DefaultDesktopManager}.
+     */
+    public DefaultDesktopManager() {}
+
     /** Normally this method will not be called. If it is, it
       * tries to determine the appropriate parent from the desktopIcon of the frame.
       * Will remove the desktopIcon from its parent if it successfully adds the frame.
--- old/src/java.desktop/share/classes/javax/swing/DefaultListCellRenderer.java 2020-08-19 13:39:35.896232800 +0530
+++ new/src/java.desktop/share/classes/javax/swing/DefaultListCellRenderer.java 2020-08-19 13:39:33.442200500 +0530
@@ -351,5 +351,9 @@
     public static class UIResource extends DefaultListCellRenderer
         implements javax.swing.plaf.UIResource
     {
+        /**
+         * Constructs a {@code UIResource}.
+         */
+        public UIResource() {}
     }
 }
--- old/src/java.desktop/share/classes/javax/swing/DefaultListModel.java    2020-08-19 13:39:48.132554100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/DefaultListModel.java    2020-08-19 13:39:46.023376700 +0530
@@ -58,6 +58,11 @@
     private Vector<E> delegate = new Vector<E>();

     /**
+     * Constructs a {@code DefaultListModel}.
+     */
+    public DefaultListModel() {}
+
+    /**
      * Returns the number of components in this list.
      * <p>
      * This method is identical to {@code size}, which implements the
--- old/src/java.desktop/share/classes/javax/swing/DefaultListSelectionModel.java   2020-08-19 13:40:01.004521400 +0530
+++ new/src/java.desktop/share/classes/javax/swing/DefaultListSelectionModel.java   2020-08-19 13:39:58.580135400 +0530
@@ -78,6 +78,11 @@
      */
     protected boolean leadAnchorNotificationEnabled = true;

+    /**
+     * Constructs a {@code DefaultListSelectionModel}.
+     */
+    public DefaultListSelectionModel() {}
+
     /** {@inheritDoc} */
     public int getMinSelectionIndex() { return isSelectionEmpty() ? -1 : minIndex; }

--- old/src/java.desktop/share/classes/javax/swing/DefaultSingleSelectionModel.java 2020-08-19 13:40:15.062885900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/DefaultSingleSelectionModel.java 2020-08-19 13:40:12.581486200 +0530
@@ -59,6 +59,11 @@
     private int index = -1;

     /**
+     * Constructs a {@code DefaultSingleSelectionModel}.
+     */
+    public DefaultSingleSelectionModel() {}
+
+    /**
      * {@inheritDoc}
      */
     public int getSelectedIndex() {
--- old/src/java.desktop/share/classes/javax/swing/FocusManager.java    2020-08-19 13:40:33.663755300 +0530
+++ new/src/java.desktop/share/classes/javax/swing/FocusManager.java    2020-08-19 13:40:30.481403700 +0530
@@ -65,6 +65,11 @@
     private static boolean enabled = true;

     /**
+     * Constructor for subclasses to call.
+     */
+    protected FocusManager() {}
+
+    /**
      * Returns the current <code>KeyboardFocusManager</code> instance
      * for the calling thread's context.
      *
--- old/src/java.desktop/share/classes/javax/swing/InputVerifier.java   2020-08-19 13:40:47.662072500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/InputVerifier.java   2020-08-19 13:40:45.537317300 +0530
@@ -99,6 +99,11 @@
 public abstract class InputVerifier {

     /**
+     * Constructor for subclasses to call.
+     */
+    protected InputVerifier() {}
+
+    /**
      * Checks whether the JComponent's input is valid. This method should
      * have no side effects. It returns a boolean indicating the status
      * of the argument's input.
--- old/src/java.desktop/share/classes/javax/swing/InternalFrameFocusTraversalPolicy.java   2020-08-19 13:41:00.966203500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/InternalFrameFocusTraversalPolicy.java   2020-08-19 13:40:58.595364200 +0530
@@ -42,6 +42,10 @@
 public abstract class InternalFrameFocusTraversalPolicy
     extends FocusTraversalPolicy
 {
+    /**
+     * Constructor for subclasses to call.
+     */
+    protected InternalFrameFocusTraversalPolicy() {}

     /**
      * Returns the Component that should receive the focus when a
--- old/src/java.desktop/share/classes/javax/swing/JFormattedTextField.java 2020-08-19 13:41:13.637202700 +0530
+++ new/src/java.desktop/share/classes/javax/swing/JFormattedTextField.java 2020-08-19 13:41:11.572384900 +0530
@@ -870,6 +870,11 @@
      */
     public abstract static class AbstractFormatterFactory {
         /**
+         * Constructor for subclasses to call.
+         */
+        protected AbstractFormatterFactory() {}
+
+        /**
          * Returns an <code>AbstractFormatter</code> that can handle formatting
          * of the passed in <code>JFormattedTextField</code>.
          *
@@ -915,6 +920,11 @@
         private JFormattedTextField ftf;

         /**
+         * Constructor for subclasses to call.
+         */
+        protected AbstractFormatter() {}
+
+        /**
          * Installs the <code>AbstractFormatter</code> onto a particular
          * <code>JFormattedTextField</code>.
          * This will invoke <code>valueToString</code> to convert the
--- old/src/java.desktop/share/classes/javax/swing/LookAndFeel.java 2020-08-19 13:41:26.024720500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/LookAndFeel.java 2020-08-19 13:41:23.818024300 +0530
@@ -151,6 +151,10 @@
  */
 public abstract class LookAndFeel
 {
+    /**
+     * Constructor for subclasses to call.
+     */
+    protected LookAndFeel() {}

     /**
      * Convenience method for setting a component's foreground
--- old/src/java.desktop/share/classes/javax/swing/MenuSelectionManager.java    2020-08-19 13:41:38.122153500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/MenuSelectionManager.java    2020-08-19 13:41:36.044212700 +0530
@@ -52,6 +52,11 @@
                        new StringBuilder("javax.swing.MenuSelectionManager");

     /**
+     * Constructs a {@code MenuSelectionManager}.
+     */
+    public MenuSelectionManager() {}
+
+    /**
      * Returns the default menu selection manager.
      *
      * @return a MenuSelectionManager object
--- old/src/java.desktop/share/classes/javax/swing/PopupFactory.java    2020-08-19 13:41:50.784686000 +0530
+++ new/src/java.desktop/share/classes/javax/swing/PopupFactory.java    2020-08-19 13:41:48.212379200 +0530
@@ -115,6 +115,10 @@
      */
     private int popupType = LIGHT_WEIGHT_POPUP;

+    /**
+     * Constructs a {@code PopupFactory}.
+     */
+    public PopupFactory() {}

     /**
      * Sets the <code>PopupFactory</code> that will be used to obtain
--- old/src/java.desktop/share/classes/javax/swing/RowFilter.java   2020-08-19 13:42:03.643804100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/RowFilter.java   2020-08-19 13:42:01.122577600 +0530
@@ -129,6 +129,11 @@
     }

     /**
+     * Constructor for subclasses to call.
+     */
+    protected RowFilter() {}
+
+    /**
      * Throws an IllegalArgumentException if any of the values in
      * columns are {@literal <} 0.
      */
--- old/src/java.desktop/share/classes/javax/swing/ScrollPaneLayout.java    2020-08-19 13:42:18.124228900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/ScrollPaneLayout.java    2020-08-19 13:42:15.696322700 +0530
@@ -154,6 +154,10 @@
      */
     protected int hsbPolicy = HORIZONTAL_SCROLLBAR_AS_NEEDED;

+    /**
+     * Constructs a {@code ScrollPaneLayout}.
+     */
+    public ScrollPaneLayout() {}

     /**
      * This method is invoked after the ScrollPaneLayout is set as the
@@ -1116,5 +1120,10 @@
     /**
      * The UI resource version of <code>ScrollPaneLayout</code>.
      */
-    public static class UIResource extends ScrollPaneLayout implements javax.swing.plaf.UIResource {}
+    public static class UIResource extends ScrollPaneLayout implements javax.swing.plaf.UIResource {
+        /**
+         * Constructs a {@code UIResource}.
+         */
+        public UIResource() {}
+    }
 }
--- old/src/java.desktop/share/classes/javax/swing/UIManager.java   2020-08-19 13:42:30.799514800 +0530
+++ new/src/java.desktop/share/classes/javax/swing/UIManager.java   2020-08-19 13:42:28.750321300 +0530
@@ -235,6 +235,11 @@
     private static final Object classLock = new Object();

     /**
+     * Constructs a {@code UIManager}.
+     */
+    public UIManager() {}
+
+    /**
      * Return the <code>LAFState</code> object, lazily create one if necessary.
      * All access to the <code>LAFState</code> fields is done via this method,
      * for example:
--- old/src/java.desktop/share/classes/javax/swing/ViewportLayout.java  2020-08-19 13:42:43.385657600 +0530
+++ new/src/java.desktop/share/classes/javax/swing/ViewportLayout.java  2020-08-19 13:42:41.167560600 +0530
@@ -64,6 +64,11 @@
     static ViewportLayout SHARED_INSTANCE = new ViewportLayout();

     /**
+     * Constructs a {@code ViewportLayout}.
+     */
+    public ViewportLayout() {}
+
+    /**
      * Adds the specified component to the layout. Not used by this class.
      * @param name the name of the component
      * @param c the component to be added
--- old/src/java.desktop/share/classes/javax/swing/border/AbstractBorder.java   2020-08-19 13:42:58.801705200 +0530
+++ new/src/java.desktop/share/classes/javax/swing/border/AbstractBorder.java   2020-08-19 13:42:56.523501200 +0530
@@ -50,6 +50,11 @@
 public abstract class AbstractBorder implements Border, Serializable
 {
     /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractBorder() {}
+
+    /**
      * This default implementation does no painting.
      * @param c the component for which this border is being painted
      * @param g the paint graphics
--- old/src/java.desktop/share/classes/javax/swing/colorchooser/AbstractColorChooserPanel.java  2020-08-19 13:43:11.913209900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/colorchooser/AbstractColorChooserPanel.java  2020-08-19 13:43:09.669832900 +0530
@@ -74,6 +74,11 @@
     private JColorChooser chooser;

     /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractColorChooserPanel() {}
+
+    /**
       * Invoked automatically when the model's state changes.
       * It is also called by <code>installChooserPanel</code> to allow
       * you to set up the initial state of your chooser.
--- old/src/java.desktop/share/classes/javax/swing/event/EventListenerList.java 2020-08-19 13:43:24.585777500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/event/EventListenerList.java 2020-08-19 13:43:22.125740000 +0530
@@ -105,6 +105,11 @@
     protected transient volatile Object[] listenerList = NULL_ARRAY;

     /**
+     * Constructs a {@code EventListenerList}.
+     */
+    public EventListenerList() {}
+
+    /**
      * Passes back the event listener list as an array
      * of ListenerType-listener pairs.  Note that for
      * performance reasons, this implementation passes back
--- old/src/java.desktop/share/classes/javax/swing/event/InternalFrameAdapter.java  2020-08-19 13:43:37.140192100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/event/InternalFrameAdapter.java  2020-08-19 13:43:34.906007200 +0530
@@ -42,6 +42,11 @@
  */
 public abstract class InternalFrameAdapter implements InternalFrameListener {
     /**
+     * Constructor for subclasses to call.
+     */
+    protected InternalFrameAdapter() {}
+
+    /**
      * Invoked when an internal frame has been opened.
      */
     public void internalFrameOpened(InternalFrameEvent e) {}
--- old/src/java.desktop/share/classes/javax/swing/event/MouseInputAdapter.java 2020-08-19 13:43:50.211518100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/event/MouseInputAdapter.java 2020-08-19 13:43:47.711429200 +0530
@@ -39,4 +39,8 @@
  */
 public abstract class MouseInputAdapter extends MouseAdapter
                                         implements MouseInputListener {
+    /**
+     * Constructor for subclasses to call.
+     */
+    protected MouseInputAdapter() {}
 }
--- old/src/java.desktop/share/classes/javax/swing/filechooser/FileFilter.java  2020-08-19 13:44:02.857215600 +0530
+++ new/src/java.desktop/share/classes/javax/swing/filechooser/FileFilter.java  2020-08-19 13:44:00.666226000 +0530
@@ -50,6 +50,11 @@
  */
 public abstract class FileFilter {
     /**
+     * Constructor for subclasses to call.
+     */
+    protected FileFilter() {}
+
+    /**
      * Whether the given file is accepted by this filter.
      *
      * @param f the File to test
--- old/src/java.desktop/share/classes/javax/swing/filechooser/FileView.java    2020-08-19 13:44:15.512320500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/filechooser/FileView.java    2020-08-19 13:44:13.455569100 +0530
@@ -67,6 +67,11 @@
  */
 public abstract class FileView {
     /**
+     * Constructor for subclasses to call.
+     */
+    protected FileView() {}
+
+    /**
      * The name of the file. Normally this would be simply
      * <code>f.getName()</code>.
      *
--- old/src/java.desktop/share/classes/javax/swing/table/AbstractTableModel.java    2020-08-19 13:44:28.259764900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/table/AbstractTableModel.java    2020-08-19 13:44:26.114664300 +0530
@@ -67,6 +67,11 @@
     /** List of listeners */
     protected EventListenerList listenerList = new EventListenerList();

+    /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractTableModel() {}
+
 //
 // Default Implementation of the Interface
 //
--- old/src/java.desktop/share/classes/javax/swing/table/DefaultTableCellRenderer.java  2020-08-19 13:44:40.607670100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/table/DefaultTableCellRenderer.java  2020-08-19 13:44:38.435469300 +0530
@@ -400,6 +400,10 @@
     public static class UIResource extends DefaultTableCellRenderer
         implements javax.swing.plaf.UIResource
     {
+        /**
+         * Constructs a {@code UIResource}.
+         */
+        public UIResource() {}
     }

 }
--- old/src/java.desktop/share/classes/javax/swing/table/TableStringConverter.java  2020-08-19 13:44:53.727231000 +0530
+++ new/src/java.desktop/share/classes/javax/swing/table/TableStringConverter.java  2020-08-19 13:44:51.074466600 +0530
@@ -33,6 +33,11 @@
  */
 public abstract class TableStringConverter {
     /**
+     * Constructor for subclasses to call.
+     */
+    protected TableStringConverter() {}
+
+    /**
      * Returns the string representation of the value at the specified
      * location.
      *
--- old/src/java.desktop/share/classes/javax/swing/text/DefaultTextUI.java  2020-08-19 13:45:07.803714200 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/DefaultTextUI.java  2020-08-19 13:45:05.436890600 +0530
@@ -37,6 +37,9 @@
  */
 @Deprecated
 public abstract class DefaultTextUI extends BasicTextUI {
-
+    /**
+     * Constructor for subclasses to call.
+     */
+    protected DefaultTextUI() {}

 }
--- old/src/java.desktop/share/classes/javax/swing/text/DocumentFilter.java 2020-08-19 13:45:20.548443500 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/DocumentFilter.java 2020-08-19 13:45:18.243731400 +0530
@@ -61,6 +61,11 @@
  */
 public class DocumentFilter {
     /**
+     * Constructs a {@code DocumentFilter}.
+     */
+    public DocumentFilter() {}
+
+    /**
      * Invoked prior to removal of the specified region in the
      * specified Document. Subclasses that want to conditionally allow
      * removal should override this and only call supers implementation as
@@ -131,6 +136,11 @@
      */
     public abstract static class FilterBypass {
         /**
+         * Constructor for subclasses to call.
+         */
+        protected FilterBypass() {}
+
+        /**
          * Returns the Document the mutation is occurring on.
          *
          * @return Document that remove/insertString will operate on
--- old/src/java.desktop/share/classes/javax/swing/text/FlowView.java   2020-08-19 13:45:33.059413800 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/FlowView.java   2020-08-19 13:45:30.984412400 +0530
@@ -341,6 +341,11 @@
      * @since 1.3
      */
     public static class FlowStrategy {
+        /**
+         * Constructs a {@code FlowStrategy}.
+         */
+        public FlowStrategy() {}
+
         Position damageStart = null;
         Vector<View> viewBuffer;

--- old/src/java.desktop/share/classes/javax/swing/text/GlyphView.java  2020-08-19 13:45:45.513919900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/GlyphView.java  2020-08-19 13:45:43.371330400 +0530
@@ -1140,6 +1140,11 @@
     public abstract static class GlyphPainter {

         /**
+         * Constructor for subclasses to call.
+         */
+        protected GlyphPainter() {}
+
+        /**
          * Determine the span the glyphs given a start location
          * (for tab expansion).
          * @param v  the {@code GlyphView}
--- old/src/java.desktop/share/classes/javax/swing/text/LayeredHighlighter.java 2020-08-19 13:45:58.222810900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/LayeredHighlighter.java 2020-08-19 13:45:56.114963600 +0530
@@ -35,6 +35,11 @@
  */
 public abstract class LayeredHighlighter implements Highlighter {
     /**
+     * Constructor for subclasses to call.
+     */
+    protected LayeredHighlighter() {}
+
+    /**
      * When leaf Views (such as LabelView) are rendering they should
      * call into this method. If a highlight is in the given region it will
      * be drawn immediately.
@@ -57,6 +62,11 @@
      */
     public abstract static class LayerPainter implements Highlighter.HighlightPainter {
         /**
+         * Constructor for subclasses to call.
+         */
+        protected LayerPainter() {}
+
+        /**
          * @return a shape
          * @param g Graphics used to draw
          * @param p0 starting offset of view
--- old/src/java.desktop/share/classes/javax/swing/text/NavigationFilter.java   2020-08-19 13:46:10.993575300 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/NavigationFilter.java   2020-08-19 13:46:08.795601700 +0530
@@ -50,6 +50,11 @@
  */
 public class NavigationFilter {
     /**
+     * Constructs a {@code NavigationFilter}.
+     */
+    public NavigationFilter() {}
+
+    /**
      * Invoked prior to the Caret setting the dot. The default implementation
      * calls directly into the <code>FilterBypass</code> with the passed
      * in arguments. Subclasses may wish to conditionally
@@ -122,6 +127,11 @@
      */
     public abstract static class FilterBypass {
         /**
+         * Constructor for subclasses to call.
+         */
+        protected FilterBypass() {}
+
+        /**
          * Returns the Caret that is changing.
          *
          * @return Caret that is changing
--- old/src/java.desktop/share/classes/javax/swing/text/Utilities.java  2020-08-19 13:46:23.440604300 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/Utilities.java  2020-08-19 13:46:21.348230100 +0530
@@ -50,6 +50,11 @@
  */
 public class Utilities {
     /**
+     * Constructs a {@code Utilities}.
+     */
+    public Utilities() {}
+
+    /**
      * If <code>view</code>'s container is a <code>JComponent</code> it
      * is returned, after casting.
      */
--- old/src/java.desktop/share/classes/javax/swing/text/html/HTML.java  2020-08-19 13:46:36.888359100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/html/HTML.java  2020-08-19 13:46:34.112527500 +0530
@@ -41,6 +41,11 @@
 public class HTML {

     /**
+     * Constructs a {@code HTML}.
+     */
+    public HTML() {}
+
+    /**
      * Typesafe enumeration for an HTML tag.  Although the
      * set of HTML tags is a closed set, we have left the
      * set open so that people can add their own tag types
--- old/src/java.desktop/share/classes/javax/swing/text/html/HTMLDocument.java  2020-08-19 13:46:49.431826700 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/html/HTMLDocument.java  2020-08-19 13:46:46.897772300 +0530
@@ -1889,6 +1889,11 @@
     public abstract static class Iterator {

         /**
+         * Constructor for subclasses to call.
+         */
+        protected Iterator() {}
+
+        /**
          * Return the attributes for this tag.
          * @return the <code>AttributeSet</code> for this tag, or
          *      <code>null</code> if none can be found
@@ -2966,6 +2971,10 @@
          * switch statement.
          */
         public class TagAction {
+            /**
+             * Constructs a {@code TagAction}.
+             */
+            public TagAction() {}

             /**
              * Called when a start tag is seen for the
@@ -3000,6 +3009,10 @@
          * Action assigned by default to handle the Block task of the reader.
          */
         public class BlockAction extends TagAction {
+            /**
+             * Constructs a {@code BlockAction}.
+             */
+            public BlockAction() {}

             public void start(HTML.Tag t, MutableAttributeSet attr) {
                 blockOpen(t, attr);
@@ -3041,6 +3054,11 @@
          */
         public class ParagraphAction extends BlockAction {

+            /**
+             * Constructs a {@code ParagraphAction}.
+             */
+            public ParagraphAction() {}
+
             public void start(HTML.Tag t, MutableAttributeSet a) {
                 super.start(t, a);
                 inParagraph = true;
@@ -3056,6 +3074,10 @@
          * Action assigned by default to handle the Special task of the reader.
          */
         public class SpecialAction extends TagAction {
+            /**
+             * Constructs a {@code SpecialAction}.
+             */
+            public SpecialAction() {}

             public void start(HTML.Tag t, MutableAttributeSet a) {
                 addSpecialElement(t, a);
@@ -3068,6 +3090,11 @@
          */
         public class IsindexAction extends TagAction {

+            /**
+             * Constructs a {@code IsindexAction}.
+             */
+            public IsindexAction() {}
+
             public void start(HTML.Tag t, MutableAttributeSet a) {
                 blockOpen(HTML.Tag.IMPLIED, new SimpleAttributeSet());
                 addSpecialElement(t, a);
@@ -3082,6 +3109,11 @@
          */
         public class HiddenAction extends TagAction {

+            /**
+             * Constructs a {@code HiddenAction}.
+             */
+            public HiddenAction() {}
+
             public void start(HTML.Tag t, MutableAttributeSet a) {
                 addSpecialElement(t, a);
             }
@@ -3311,6 +3343,11 @@
          */
         public class PreAction extends BlockAction {

+            /**
+             * Constructs a {@code PreAction}.
+             */
+            public PreAction() {}
+
             public void start(HTML.Tag t, MutableAttributeSet attr) {
                 inPre = true;
                 blockOpen(t, attr);
@@ -3332,6 +3369,11 @@
          */
         public class CharacterAction extends TagAction {

+            /**
+             * Constructs a {@code CharacterAction}.
+             */
+            public CharacterAction() {}
+
             public void start(HTML.Tag t, MutableAttributeSet attr) {
                 pushCharacterStyle();
                 if (!foundInsertTag) {
@@ -3584,6 +3626,11 @@
          */
         public class FormAction extends SpecialAction {

+            /**
+             * Constructs a {@code FormAction}.
+             */
+            public FormAction() {}
+
             public void start(HTML.Tag t, MutableAttributeSet attr) {
                 if (t == HTML.Tag.INPUT) {
                     String type = (String)
--- old/src/java.desktop/share/classes/javax/swing/text/html/HTMLEditorKit.java 2020-08-19 13:47:02.152518200 +0530
+++ new/src/java.desktop/share/classes/javax/swing/text/html/HTMLEditorKit.java 2020-08-19 13:46:59.952555400 +0530
@@ -675,6 +675,11 @@
         private int curOffset;

         /**
+         * Constructs a {@code LinkController}.
+         */
+        public LinkController() {}
+
+        /**
          * Called for a mouse click event.
          * If the component is read-only (ie a browser) then
          * the clicked event is used to drive an attempt to
@@ -990,6 +995,11 @@
      */
     public abstract static class Parser {
         /**
+         * Constructor for subclasses to call.
+         */
+        protected Parser() {}
+
+        /**
          * Parse the given stream and drive the given callback
          * with the results of the parse.  This method should
          * be implemented to be thread-safe.
@@ -1017,6 +1027,11 @@
      */
     public static class ParserCallback {
         /**
+         * Constructs a {@code ParserCallback}.
+         */
+        public ParserCallback() {}
+
+        /**
          * This is passed as an attribute in the attributeset to indicate
          * the element is implied eg, the string '&lt;&gt;foo&lt;\t&gt;'
          * contains an implied html element and an implied body element.
@@ -1236,6 +1251,10 @@
      * </table>
      */
     public static class HTMLFactory implements ViewFactory {
+        /**
+         * Constructs a {@code HTMLFactory}.
+         */
+        public HTMLFactory() {}

         /**
          * Creates a view from an element.
--- old/src/java.desktop/share/classes/javax/swing/tree/AbstractLayoutCache.java    2020-08-19 13:47:18.628292900 +0530
+++ new/src/java.desktop/share/classes/javax/swing/tree/AbstractLayoutCache.java    2020-08-19 13:47:15.692403000 +0530
@@ -64,6 +64,10 @@
       */
     protected int                rowHeight;

+    /**
+     * Constructor for subclasses to call.
+     */
+    protected AbstractLayoutCache() {}

     /**
      * Sets the renderer that is responsible for drawing nodes in the tree
@@ -511,6 +515,11 @@
      */
     public abstract static class NodeDimensions {
         /**
+         * Constructor for subclasses to call.
+         */
+        protected NodeDimensions() {}
+
+        /**
          * Returns, by reference in bounds, the size and x origin to
          * place value at. The calling method is responsible for determining
          * the Y location. If bounds is <code>null</code>, a newly created
--- old/src/java.desktop/share/classes/javax/swing/undo/CannotRedoException.java    2020-08-19 13:47:31.868025100 +0530
+++ new/src/java.desktop/share/classes/javax/swing/undo/CannotRedoException.java    2020-08-19 13:47:29.765698600 +0530
@@ -40,4 +40,8 @@
  */
 @SuppressWarnings("serial") // Same-version serialization only
 public class CannotRedoException extends RuntimeException {
+    /**
+     * Constructs a {@code CannotRedoException}.
+     */
+    public CannotRedoException() {}
 }
--- old/src/java.desktop/share/classes/javax/swing/undo/CannotUndoException.java    2020-08-19 13:47:43.994836600 +0530
+++ new/src/java.desktop/share/classes/javax/swing/undo/CannotUndoException.java    2020-08-19 13:47:41.923992200 +0530
@@ -41,4 +41,8 @@
  */
 @SuppressWarnings("serial") // Same-version serialization only
 public class CannotUndoException extends RuntimeException {
+    /**
+     * Constructs a {@code CannotUndoException}.
+     */
+    public CannotUndoException() {}
 }
--- old/src/jdk.unsupported.desktop/share/classes/jdk/swing/interop/SwingInterOpUtils.java  2020-08-19 13:47:56.623746600 +0530
+++ new/src/jdk.unsupported.desktop/share/classes/jdk/swing/interop/SwingInterOpUtils.java  2020-08-19 13:47:54.494092100 +0530
@@ -41,6 +41,11 @@
  */
 public class SwingInterOpUtils {

+    /**
+     * Constructs a {@code SwingInterOpUtils}.
+     */
+    public SwingInterOpUtils() {}
+
     public static void postEvent(Object target, java.awt.AWTEvent e) {
         AppContext context = SunToolkit.targetToAppContext(target);
         if (context != null) {