From 674cc3eeca77f1f2a6d937b1df5c5cd8a13c2d31 Mon Sep 17 00:00:00 2001
From: Prasanta Sadhukhan <psadhukhan@openjdk.org>
Date: Fri, 5 Dec 2025 03:30:31 +0000
Subject: [PATCH] 8042054: JTree.updateUI uses out-of-date item size
 information

Reviewed-by: dnguyen, serb
---
 .../share/classes/javax/swing/JTree.java      |  6 +-
 .../javax/swing/JTree/JTreeUpdateTest.java    | 96 +++++++++++++++++++
 2 files changed, 99 insertions(+), 3 deletions(-)
 create mode 100644 test/jdk/javax/swing/JTree/JTreeUpdateTest.java

diff --git a/src/java.desktop/share/classes/javax/swing/JTree.java b/src/java.desktop/share/classes/javax/swing/JTree.java
index c081b3cfff8..622c55e2ede 100644
--- a/src/java.desktop/share/classes/javax/swing/JTree.java
+++ b/src/java.desktop/share/classes/javax/swing/JTree.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2025, 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
@@ -777,10 +777,10 @@ public class JTree extends JComponent implements Scrollable, Accessible
             updateInProgress = true;
 
             try {
-                setUI((TreeUI)UIManager.getUI(this));
-
                 SwingUtilities.updateRendererOrEditorUI(getCellRenderer());
                 SwingUtilities.updateRendererOrEditorUI(getCellEditor());
+
+                setUI((TreeUI)UIManager.getUI(this));
             } finally {
                 updateInProgress = false;
             }
diff --git a/test/jdk/javax/swing/JTree/JTreeUpdateTest.java b/test/jdk/javax/swing/JTree/JTreeUpdateTest.java
new file mode 100644
index 00000000000..6b0a4f03c29
--- /dev/null
+++ b/test/jdk/javax/swing/JTree/JTreeUpdateTest.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2025, 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 8042054
+ * @summary JTree.updateUI should use updated item size information
+ * @library /java/awt/regtesthelpers
+ * @build PassFailJFrame
+ * @run main/manual JTreeUpdateTest
+ */
+
+import java.awt.BorderLayout;
+import java.awt.Dimension;
+import javax.swing.BorderFactory;
+import javax.swing.JFrame;
+import javax.swing.JTree;
+import javax.swing.SwingUtilities;
+import javax.swing.tree.DefaultTreeCellRenderer;
+import javax.swing.UIManager;
+
+public class JTreeUpdateTest {
+
+    static final String INSTRUCTIONS = """
+        A frame with two identical JTrees is shown.
+        If the left JTree's text is abbreviated and JTree items
+        are cramped with little space between rows then press Fail.
+        If the left JTree is identical with right JTree, press Pass.
+    """;
+
+    public static void main(String[] args) throws Exception {
+        PassFailJFrame.builder()
+                .title("JTreeUpdateTest Test instructions")
+                .instructions(INSTRUCTIONS)
+                .columns(30)
+                .testUI(JTreeUpdateTest::createUI)
+                .build()
+                .awaitAndCheck();
+    }
+
+    private static JFrame createUI() {
+        setLaf("javax.swing.plaf.metal.MetalLookAndFeel");
+
+        final JFrame frame = new JFrame("JTreeUpdateTest");
+
+        final JTree tree = new JTree();
+        tree.setPreferredSize(new Dimension(200, 200));
+        tree.setCellRenderer(new DefaultTreeCellRenderer());
+        tree.setBorder(BorderFactory.createTitledBorder("updateUI() called once"));
+        frame.add(tree);
+
+        final JTree tree2 = new JTree();
+        tree2.setPreferredSize(new Dimension(200, 200));
+        tree2.setCellRenderer(new DefaultTreeCellRenderer());
+        tree2.setBorder(BorderFactory.createTitledBorder("updateUI() called twice"));
+        frame.add(tree2, BorderLayout.EAST);
+
+        frame.pack();
+        frame.setLocationRelativeTo(null);
+
+        SwingUtilities.invokeLater(() -> {
+            setLaf("javax.swing.plaf.nimbus.NimbusLookAndFeel");
+            SwingUtilities.updateComponentTreeUI(frame);
+            SwingUtilities.updateComponentTreeUI(tree2);
+        });
+        return frame;
+    }
+
+    private static void setLaf(String className) {
+        try {
+            UIManager.setLookAndFeel(className);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+}