Fix 442 style property race

odfdom/pom.xml

@@ -195,7 +195,7 @@
                 <artifactId>maven-surefire-plugin</artifactId>
                 <configuration>
                     <useModulePath>false</useModulePath>
-                    <argLine>-javaagent:${settings.localRepository}/org/jacoco/org.jacoco.agent/${jacoco.version}/org.jacoco.agent-${jacoco.version}-runtime.jar=destfile=${project.build.directory}/coverage-reports/jacoco-ut.exec</argLine>
+                    <argLine>-javaagent:${settings.localRepository}/org/jacoco/org.jacoco.agent/${jacoco.version}/org.jacoco.agent-${jacoco.version}-runtime.jar=destfile=${project.build.directory}/coverage-reports/jacoco-ut.exec,excludes=${jacoco.agent.excludes}</argLine>
                     <systemPropertyVariables>
                         <org.odftoolkit.odfdom.validation>true</org.odftoolkit.odfdom.validation>
                     </systemPropertyVariables>

odfdom/src/main/java/org/odftoolkit/odfdom/dom/style/props/OdfStyleProperty.java

@@ -23,8 +23,8 @@
  */
 package org.odftoolkit.odfdom.dom.style.props;
 
-import java.util.Iterator;
-import java.util.TreeSet;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import org.odftoolkit.odfdom.pkg.OdfName;
 
 /**
@@ -33,15 +33,18 @@
  */
 public class OdfStyleProperty implements Comparable<OdfStyleProperty> {
 
-  private OdfStylePropertiesSet m_propSet;
-  private OdfName m_name;
+  private final OdfStylePropertiesSet m_propSet;
+  private final OdfName m_name;
 
   private OdfStyleProperty(OdfStylePropertiesSet propSet, OdfName name) {
     m_propSet = propSet;
     m_name = name;
   }
 
-  private static TreeSet<OdfStyleProperty> m_styleProperties = new TreeSet<>();
+  // Concurrent map, as the static initializers of the generated Style*PropertiesElement classes
+  // might register their properties from different threads at the same time (see issue #442)
+  private static final Map<OdfStyleProperty, OdfStyleProperty> m_styleProperties =
+      new ConcurrentHashMap<>();
 
   /**
    * Looks if an OdfStyleProperty is already listed in the static sytleProperties set, otherwise
@@ -53,26 +56,8 @@ private OdfStyleProperty(OdfStylePropertiesSet propSet, OdfName name) {
    */
   public static OdfStyleProperty get(OdfStylePropertiesSet propSet, OdfName name) {
     OdfStyleProperty temp = new OdfStyleProperty(propSet, name);
-    // Replacement for (JDK1.6)
-    // OdfStyleProperty result = m_styleProperties.floor(temp);
-
-    Iterator<OdfStyleProperty> iter = m_styleProperties.iterator();
-    OdfStyleProperty result = null;
-
-    // check if key exists
-    if (!m_styleProperties.contains(temp)) {
-      m_styleProperties.add(temp);
-      return temp;
-    }
-    while (iter.hasNext()) {
-      result = iter.next();
-      if (result.equals(temp)) {
-        return result;
-      }
-    }
-
-    m_styleProperties.add(temp);
-    return temp;
+    OdfStyleProperty existing = m_styleProperties.putIfAbsent(temp, temp);
+    return existing != null ? existing : temp;
   }
 
   /** @return an OdfStylePropertiesSet member */

odfdom/src/test/java/org/odftoolkit/odfdom/dom/style/props/OdfStylePropertyConcurrencyTest.java

@@ -0,0 +1,179 @@
+/**
+ * **********************************************************************
+ *
+ * <p>DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
+ *
+ * <p>Copyright 2026 The Document Foundation.
+ *
+ * <p>Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0. You can also obtain a copy of the License at
+ * http://odftoolkit.org/docs/license.txt
+ *
+ * <p>Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied.
+ *
+ * <p>See the License for the specific language governing permissions and limitations under the
+ * License.
+ *
+ * <p>**********************************************************************
+ */
+package org.odftoolkit.odfdom.dom.style.props;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import org.junit.Test;
+import org.odftoolkit.odfdom.dom.OdfDocumentNamespace;
+import org.odftoolkit.odfdom.pkg.OdfName;
+
+/**
+ * Regression tests for concurrent registration of style properties, see
+ * https://github.com/tdf/odftoolkit/issues/442
+ */
+public class OdfStylePropertyConcurrencyTest {
+
+  private static final int THREADS = 32;
+  private static final int OPERATIONS_PER_THREAD = 5_000;
+  private static final long TIMEOUT_SECONDS = 60;
+
+  private static final String[] STYLE_PROPERTIES_ELEMENTS = {
+    "StyleChartPropertiesElement",
+    "StyleDrawingPagePropertiesElement",
+    "StyleGraphicPropertiesElement",
+    "StyleHeaderFooterPropertiesElement",
+    "StyleListLevelPropertiesElement",
+    "StylePageLayoutPropertiesElement",
+    "StyleParagraphPropertiesElement",
+    "StyleRubyPropertiesElement",
+    "StyleSectionPropertiesElement",
+    "StyleTableCellPropertiesElement",
+    "StyleTableColumnPropertiesElement",
+    "StyleTablePropertiesElement",
+    "StyleTableRowPropertiesElement",
+    "StyleTextPropertiesElement"
+  };
+
+  /** Many threads register different new properties at the same time. */
+  @Test
+  public void testConcurrentRegistration() throws Exception {
+    OdfStylePropertiesSet[] propSets = OdfStylePropertiesSet.values();
+    List<List<OdfStyleProperty>> results =
+        runConcurrently(
+            worker -> {
+              List<OdfStyleProperty> props = new ArrayList<>(OPERATIONS_PER_THREAD);
+              for (int i = 0; i < OPERATIONS_PER_THREAD; i++) {
+                OdfStylePropertiesSet propSet = propSets[(worker + i) % propSets.length];
+                OdfName name =
+                    OdfName.newName(
+                        OdfDocumentNamespace.TEXT, "race-unique-property-" + worker + "-" + i);
+                OdfStyleProperty prop = OdfStyleProperty.get(propSet, name);
+                assertSame(propSet, prop.getPropertySet());
+                assertSame(name, prop.getName());
+                props.add(prop);
+              }
+              return props;
+            });
+    // all properties have been registered and are found again
+    for (List<OdfStyleProperty> props : results) {
+      for (OdfStyleProperty prop : props) {
+        assertSame(prop, OdfStyleProperty.get(prop.getPropertySet(), prop.getName()));
+      }
+    }
+  }
+
+  /** Many threads register the same new properties at the same time and share one instance. */
+  @Test
+  public void testConcurrentCanonicalization() throws Exception {
+    List<List<OdfStyleProperty>> results =
+        runConcurrently(
+            worker -> {
+              List<OdfStyleProperty> props = new ArrayList<>(OPERATIONS_PER_THREAD);
+              for (int i = 0; i < OPERATIONS_PER_THREAD; i++) {
+                props.add(
+                    OdfStyleProperty.get(
+                        OdfStylePropertiesSet.TextProperties,
+                        OdfName.newName(OdfDocumentNamespace.TEXT, "race-shared-property-" + i)));
+              }
+              return props;
+            });
+    List<OdfStyleProperty> expected = results.get(0);
+    for (List<OdfStyleProperty> props : results) {
+      assertEquals(OPERATIONS_PER_THREAD, props.size());
+      for (int i = 0; i < OPERATIONS_PER_THREAD; i++) {
+        assertSame(expected.get(i), props.get(i));
+      }
+    }
+  }
+
+  /**
+   * Initializes the generated Style*PropertiesElement classes concurrently, as their static
+   * initializers register their properties. This is only a real cold start, if no earlier test of
+   * the same JVM has already loaded these classes.
+   */
+  @Test
+  public void testConcurrentStylePropertiesElementInitialization() throws Exception {
+    ClassLoader loader = getClass().getClassLoader();
+    List<List<Class<?>>> results =
+        runConcurrently(
+            worker -> {
+              List<Class<?>> classes = new ArrayList<>(STYLE_PROPERTIES_ELEMENTS.length);
+              for (int i = 0; i < STYLE_PROPERTIES_ELEMENTS.length; i++) {
+                String className =
+                    "org.odftoolkit.odfdom.dom.element.style."
+                        + STYLE_PROPERTIES_ELEMENTS[(worker + i) % STYLE_PROPERTIES_ELEMENTS.length];
+                classes.add(Class.forName(className, true, loader));
+              }
+              return classes;
+            });
+    for (List<Class<?>> classes : results) {
+      assertEquals(STYLE_PROPERTIES_ELEMENTS.length, classes.size());
+    }
+  }
+
+  private interface Worker<T> {
+    T run(int worker) throws Exception;
+  }
+
+  /** Runs the given work in THREADS threads, all started at the same moment. */
+  private static <T> List<T> runConcurrently(Worker<T> work) throws Exception {
+    ExecutorService pool = Executors.newFixedThreadPool(THREADS);
+    try {
+      CountDownLatch ready = new CountDownLatch(THREADS);
+      CountDownLatch start = new CountDownLatch(1);
+      List<Future<T>> futures = new ArrayList<>(THREADS);
+      for (int thread = 0; thread < THREADS; thread++) {
+        final int worker = thread;
+        Callable<T> task =
+            () -> {
+              ready.countDown();
+              start.await();
+              return work.run(worker);
+            };
+        futures.add(pool.submit(task));
+      }
+      assertTrue(
+          "Worker threads did not start in time", ready.await(TIMEOUT_SECONDS, TimeUnit.SECONDS));
+      start.countDown();
+
+      List<T> results = new ArrayList<>(THREADS);
+      for (Future<T> future : futures) {
+        // rethrows any failure of a worker thread as ExecutionException
+        results.add(future.get(TIMEOUT_SECONDS, TimeUnit.SECONDS));
+      }
+      return results;
+    } finally {
+      pool.shutdownNow();
+    }
+  }
+}

pom.xml

@@ -58,7 +58,10 @@
         <maven.javadoc.failOnError>false</maven.javadoc.failOnError>
         <maven.build.timestamp.format>yyyy-MM-dd'T'HH:mm:ss</maven.build.timestamp.format>
         <!-- JaCoCo Properties -->
-        <jacoco.version>0.8.14</jacoco.version>
+        <jacoco.version>0.8.15</jacoco.version>
+        <!-- JDK classes are never instrumented by the JaCoCo agent, as newer JDKs might use class file
+             versions unknown to JaCoCo resulting into exceptions in the build log -->
+        <jacoco.agent.excludes>java.*:javax.*:jdk.*:sun.*:com.sun.*</jacoco.agent.excludes>
         <sonar.java.coveragePlugin>jacoco</sonar.java.coveragePlugin>
         <sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>
         <sonar.coverage.jacoco.xmlReportPaths>${project.reporting.outputDirectory}/jacoco-ut/jacoco.xml</sonar.coverage.jacoco.xmlReportPaths>
@@ -494,6 +497,9 @@
                             <configuration>
                                 <!-- Sets the path to the file which contains the execution data. -->
                                 <destFile>${project.build.directory}/coverage-reports/jacoco-ut.exec</destFile>
+                                <excludes>
+                                    <exclude>${jacoco.agent.excludes}</exclude>
+                                </excludes>
                                 <!--
                                     Sets the name of the property containing the settings
                                     for JaCoCo runtime agent.
@@ -535,6 +541,9 @@
                             <configuration>
                                 <!-- Sets the path to the file which contains the execution data. -->
                                 <destFile>${project.build.directory}/coverage-reports/jacoco-it.exec</destFile>
+                                <excludes>
+                                    <exclude>${jacoco.agent.excludes}</exclude>
+                                </excludes>
                                 <!--
                                     Sets the name of the property containing the settings
                                     for JaCoCo runtime agent.