XWIKI-14494: Java scheduler job coming from an extension is not rescheduled when the extension is upgraded

xwiki-commons-core/xwiki-commons-classloader/xwiki-commons-classloader-api/pom.xml

@@ -55,6 +55,11 @@
       <groupId>commons-io</groupId>
       <artifactId>commons-io</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.xwiki.commons</groupId>
+      <artifactId>xwiki-commons-observation-api</artifactId>
+      <version>${project.version}</version>
+    </dependency>
 
     <!-- Testing dependencies -->
     <dependency>

xwiki-commons-core/xwiki-commons-classloader/xwiki-commons-classloader-api/src/main/java/org/xwiki/classloader/internal/ClassLoaderResetEvent.java

@@ -0,0 +1,74 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.xwiki.classloader.internal;
+
+import java.util.Objects;
+
+import org.xwiki.observation.event.Event;
+import org.xwiki.stability.Unstable;
+
+/**
+ * Event triggered whenever a class loader has been dropped
+ * (see {@link org.xwiki.classloader.ClassLoaderManager#dropURLClassLoader(String)}) and reloaded. This is used for
+ * example when a JAR extension is uninstalled. Note that {@link org.xwiki.classloader.ClassLoaderManager} is not
+ * responsible for triggering this, as the trigger needs to be performed after the classloader reload.
+ *
+ * @version $Id$
+ * @since 17.1.0
+ * @since 18.0.0RC1
+ */
+@Unstable
+public class ClassLoaderResetEvent implements Event
+{
+    private final String namespace;
+
+    /**
+     * Default constructor for the root classloader.
+     */
+    public ClassLoaderResetEvent()
+    {
+        this(null);
+    }
+
+    /**
+     * Default constructor when the event is triggered for a specific namespace.
+     * @param namespace the namespace of the reset classloader.
+     */
+    public ClassLoaderResetEvent(String namespace)
+    {
+        this.namespace = namespace;
+    }
+
+    /**
+     * @return the namespace the event is triggered for.
+     */
+    public String getNamespace()
+    {
+        return namespace;
+    }
+
+    @Override
+    public boolean matches(Object otherEvent)
+    {
+        return otherEvent instanceof ClassLoaderResetEvent classLoaderResetedEvent
+            && (namespace == null
+            || Objects.equals(namespace, classLoaderResetedEvent.namespace));
+    }
+}

xwiki-commons-core/xwiki-commons-extension/xwiki-commons-extension-handlers/xwiki-commons-extension-handler-jar/pom.xml

@@ -33,9 +33,6 @@
   <description>XWiki Commons - Extension - Handler - JAR</description>
   <properties>
     <xwiki.jacoco.instructionRatio>0.81</xwiki.jacoco.instructionRatio>
-    <!-- Too many dependencies required -->
-    <checkstyle.suppressions.location>${basedir}/src/checkstyle/checkstyle-suppressions.xml
-    </checkstyle.suppressions.location>
   </properties>
   <dependencies>
     <dependency>
@@ -79,23 +76,4 @@
       <scope>test</scope>
     </dependency>
   </dependencies>
-  <build>
-    <plugins>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-checkstyle-plugin</artifactId>
-        <executions>
-          <execution>
-            <!-- Specify the "default" execution id so that the "blocker" one is always executed -->
-            <id>default</id>
-            <configuration>
-              <excludes>
-                org/xwiki/extension/jar/internal/handler/JarExtensionHandler.java
-              </excludes>
-            </configuration>
-          </execution>
-        </executions>
-      </plugin>
-    </plugins>
-  </build>
 </project>

xwiki-commons-core/xwiki-commons-extension/xwiki-commons-extension-handlers/xwiki-commons-extension-handler-jar/src/main/java/org/xwiki/extension/jar/internal/handler/JarExtensionHandler.java

@@ -110,7 +110,7 @@ public static boolean isSupported(String type)
             type.equals(JarExtensionHandler.JAR)
                 || type.equals(JarExtensionHandler.WEBJAR)
                 || type.equals(JarExtensionHandler.WEBJAR_NODE)
-        );
+                );
     }
 
     /**

xwiki-commons-core/xwiki-commons-extension/xwiki-commons-extension-handlers/xwiki-commons-extension-handler-jar/src/main/java/org/xwiki/extension/jar/internal/handler/JarExtensionJobFinishingListener.java

@@ -36,6 +36,7 @@
 
 import org.slf4j.Logger;
 import org.xwiki.classloader.ClassLoaderManager;
+import org.xwiki.classloader.internal.ClassLoaderResetEvent;
 import org.xwiki.component.annotation.Component;
 import org.xwiki.context.Execution;
 import org.xwiki.context.ExecutionContext;
@@ -51,6 +52,7 @@
 import org.xwiki.job.event.JobFinishingEvent;
 import org.xwiki.job.event.JobStartedEvent;
 import org.xwiki.observation.EventListener;
+import org.xwiki.observation.ObservationManager;
 import org.xwiki.observation.event.Event;
 
 /**
@@ -62,6 +64,8 @@
 @Component
 @Singleton
 @Named("JarExtensionJobFinishingListener")
+// Fan out of 21
+@SuppressWarnings("checkstyle:ClassFanOutComplexity")
 public class JarExtensionJobFinishingListener implements EventListener
 {
     private static final class UninstalledExtensionCollection
@@ -120,6 +124,9 @@ private void add(String namespace)
     @Inject
     private Logger logger;
 
+    @Inject
+    private ObservationManager observationManager;
+
     @Override
     public String getName()
     {
@@ -257,32 +264,31 @@ private void onJobFinishedEvent()
         if (collection != null) {
             if (collection.rootNamespace) {
                 // Unload extensions
-                unloadJARsFromNamespace(null, null);
+                unloadJARsFromNamespace(null);
 
                 // Drop class loaders
                 this.jarExtensionClassLoader.dropURLClassLoaders();
 
                 initializeExtensions(null);
+                this.observationManager.notify(new ClassLoaderResetEvent(), null);
             } else if (collection.namespaces != null) {
                 for (String namespace : collection.namespaces) {
                     // Unload extensions
-                    unloadJARsFromNamespace(namespace, null);
+                    unloadJARsFromNamespace(namespace);
 
                     // Drop class loader
                     this.jarExtensionClassLoader.dropURLClassLoader(namespace);
 
                     initializeExtensions(namespace);
+                    this.observationManager.notify(new ClassLoaderResetEvent(namespace), null);
                 }
             }
         }
     }
 
-    private void unloadJARsFromNamespace(String namespace, Map<String, Set<InstalledExtension>> unloadedExtensions)
+    private void unloadJARsFromNamespace(String namespace)
     {
-        Map<String, Set<InstalledExtension>> unloadedExtensionsMap = unloadedExtensions;
-        if (unloadedExtensionsMap == null) {
-            unloadedExtensionsMap = new HashMap<>();
-        }
+        Map<String, Set<InstalledExtension>> unloadedExtensionsMap = new HashMap<>();
 
         // Load extensions from local repository
         Collection<InstalledExtension> installedExtensions;