6257207: JTable.getDefaultEditor throws NullPointerException

Reviewed-by: tr, dnguyen, aivanov, serb

src/java.desktop/share/classes/javax/swing/JTable.java

@@ -684,6 +684,7 @@ public class JTable extends JComponent implements TableModelListener, Scrollable
                            JComponent.getManagingFocusForwardTraversalKeys());
         setFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS,
                            JComponent.getManagingFocusBackwardTraversalKeys());
+
         if (cm == null) {
             cm = createDefaultColumnModel();
             autoCreateColumnsFromModel = true;
@@ -702,7 +703,6 @@ public class JTable extends JComponent implements TableModelListener, Scrollable
             dm = createDefaultDataModel();
         }
         setModel(dm);
-
         initializeLocalVars();
         updateUI();
     }
@@ -1398,6 +1398,9 @@ public class JTable extends JComponent implements TableModelListener, Scrollable
             return null;
         }
         else {
+            if (defaultRenderersByColumnClass == null) {
+                createDefaultRenderers();
+            }
             Object renderer = defaultRenderersByColumnClass.get(columnClass);
             if (renderer != null) {
                 return (TableCellRenderer)renderer;
@@ -1455,6 +1458,9 @@ public class JTable extends JComponent implements TableModelListener, Scrollable
             return null;
         }
         else {
+            if (defaultEditorsByColumnClass == null) {
+                createDefaultEditors();
+            }
             Object editor = defaultEditorsByColumnClass.get(columnClass);
             if (editor != null) {
                 return (TableCellEditor)editor;

test/jdk/javax/swing/JTable/JTableEditorNPE.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 6257207
+ * @key headful
+ * @summary Verifies if JTable.getDefaultEditor throws NullPointerException
+ * @run main JTableEditorNPE
+ */
+import java.awt.Component;
+import javax.swing.JFrame;
+import javax.swing.JTable;
+import javax.swing.table.DefaultTableModel;
+import javax.swing.table.TableModel;
+import javax.swing.table.TableCellEditor;
+import javax.swing.table.TableCellRenderer;
+import javax.swing.event.TableModelEvent;
+import javax.swing.event.TableModelListener;
+import javax.swing.SwingUtilities;
+
+public class JTableEditorNPE {
+    private static JFrame frame;
+
+    public static void main(String[] args) throws Exception {
+        try {
+            SwingUtilities.invokeAndWait(() -> {
+                frame = new JFrame();
+                frame.setSize(100, 100);
+
+                DefaultTableModel myModel = new DefaultTableModel();
+                myModel.addColumn("Col1");
+                myModel.addColumn("Col2");
+                myModel.addColumn("Col3");
+                myModel.addRow(new Object[]{"item1.1", "item1.2", "item1.3"});
+                myModel.addRow(new Object[]{"item2.1", "item2.2", "item2.3"});
+                MyTable tbl = new MyTable(myModel);
+                frame.getContentPane().add(tbl);
+                frame.validate();
+            });
+        } finally {
+            SwingUtilities.invokeAndWait(() -> {
+                if (frame != null) {
+                    frame.dispose();
+                }
+            });
+        }
+    }
+
+    static class MyTable extends JTable implements TableModelListener {
+        public MyTable(TableModel model) {
+            super(model);
+        }
+
+        public void tableChanged(TableModelEvent event) {
+            super.tableChanged(event);
+
+            int column = event.getColumn();
+            if (column == TableModelEvent.ALL_COLUMNS) {
+                resizeAll();
+            } else {
+                resize(column);
+            }
+        }
+
+        protected void resizeAll() {
+            for (int i = 0; i < getModel().getColumnCount(); i++) {
+                resize(i);
+            }
+        }
+
+        protected void resize(int column) {
+            TableCellEditor editor = null;
+            TableCellRenderer renderer = null;
+            Component comp;
+            int width=0;
+            for (int row = 0; row < getModel().getRowCount(); row++) {
+                editor = this.getCellEditor(row, column);
+                if (editor != null) {
+                    comp = editor.getTableCellEditorComponent(
+                            this, // table
+                            getModel().getValueAt(row,column), // value
+                            false, // isSelected
+                            row, // row
+                            column // column
+                    );
+                    if (comp != null) {
+                        width = Math.max(width, comp.getPreferredSize().width);
+                    }
+                }
+
+                renderer = this.getCellRenderer(row, column);
+                if (renderer != null) {
+                    comp = renderer.getTableCellRendererComponent(
+                            this, // table
+                            getModel().getValueAt(row, column), // value
+                            false, // isSelected
+                            false, // hasFocus
+                            row, // row
+                            column // column
+                    );
+                    if (comp != null) {
+                        width = Math.max(width, comp.getPreferredSize().width);
+                    }
+                }
+            }
+
+            getColumnModel().getColumn(column).setPreferredWidth(width);
+
+            this.revalidate();
+            this.repaint();
+        }
+    }
+}
+