Avoid java.management dependency when JMX is disabled (#2775)

Co-authored-by: Piotr P. Karwasz <[email protected]>

log4j-core/pom.xml

@@ -70,8 +70,12 @@
  javax.lang.model.*;resolution:=optional,
  javax.tools;resolution:=optional,
  <!-- `java.sql`, which depends on `java.logging` is optional -->
+ java.sql;resolution:=optional,
  javax.sql;resolution:=optional,
  java.util.logging;resolution:=optional,
+ <!-- `java.management` is optional -->
+ java.lang.management;resolution:=optional,
+ javax.management.*;resolution:=optional,
  <!-- `java.naming` is optional -->
  javax.naming;resolution:=optional
  </bnd-extra-package-options>
@@ -88,6 +92,7 @@
  com.fasterxml.jackson.databind;transitive=false,
  com.fasterxml.jackson.dataformat.xml;transitive=false,
  com.fasterxml.jackson.dataformat.yaml;transitive=false,
+ java.management;transitive=false;static=true,
  java.naming;transitive=false,
  org.apache.commons.csv;transitive=false,
  org.fusesource.jansi;transitive=false,

log4j-core/src/main/java/org/apache/logging/log4j/core/LoggerContext.java

@@ -16,6 +16,7 @@
  */
 package org.apache.logging.log4j.core;
 
+import static org.apache.logging.log4j.core.jmx.internal.JmxUtil.isJmxDisabled;
 import static org.apache.logging.log4j.core.util.ShutdownCallbackRegistry.SHUTDOWN_HOOK_MARKER;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
@@ -370,12 +371,7 @@ public boolean stop(final long timeout, final TimeUnit timeUnit) {
  }
 
  this.setStopping();
- try {
- Server.unregisterLoggerContext(getName()); // LOG4J2-406, LOG4J2-500
- } catch (final LinkageError | Exception e) {
- // LOG4J2-1506 Hello Android, GAE
- LOGGER.error("Unable to unregister MBeans", e);
- }
+ unregisterJmxBeans();
  if (shutdownCallback != null) {
  shutdownCallback.cancel();
  shutdownCallback = null;
@@ -407,6 +403,17 @@ public boolean stop(final long timeout, final TimeUnit timeUnit) {
  return true;
  }
 
+ private void unregisterJmxBeans() {
+ if (!isJmxDisabled()) {
+ try {
+ Server.unregisterLoggerContext(getName()); // LOG4J2-406, LOG4J2-500
+ } catch (final LinkageError | Exception error) {
+ // LOG4J2-1506 Hello Android, GAE
+ LOGGER.error("Unable to unregister MBeans", error);
+ }
+ }
+ }
+
  /**
  * Gets the name.
  *
@@ -638,12 +645,8 @@ public Configuration setConfiguration(final Configuration config) {
 
  firePropertyChangeEvent(new PropertyChangeEvent(this, PROPERTY_CONFIG, prev, config));
 
- try {
- Server.reregisterMBeansAfterReconfigure();
- } catch (final LinkageError | Exception e) {
- // LOG4J2-716: Android has no java.lang.management
- LOGGER.error("Could not reconfigure JMX", e);
- }
+ registerJmxBeans();
+
  // AsyncLoggers update their nanoClock when the configuration changes
  Log4jLogEvent.setNanoClock(configuration.getNanoClock());
 
@@ -653,6 +656,17 @@ public Configuration setConfiguration(final Configuration config) {
  }
  }
 
+ private static void registerJmxBeans() {
+ if (!isJmxDisabled()) {
+ try {
+ Server.reregisterMBeansAfterReconfigure();
+ } catch (final LinkageError | Exception error) {
+ // LOG4J2-716: Android has no java.lang.management
+ LOGGER.error("Could not reconfigure JMX", error);
+ }
+ }
+ }
+
  private void firePropertyChangeEvent(final PropertyChangeEvent event) {
  for (final PropertyChangeListener listener : propertyChangeListeners) {
  listener.propertyChange(event);

log4j-core/src/main/java/org/apache/logging/log4j/core/jmx/Server.java

@@ -16,6 +16,8 @@
  */
 package org.apache.logging.log4j.core.jmx;
 
+import static org.apache.logging.log4j.core.jmx.internal.JmxUtil.isJmxDisabled;
+
 import java.lang.management.ManagementFactory;
 import java.util.List;
 import java.util.Map;
@@ -58,7 +60,6 @@ public final class Server {
  */
  public static final String DOMAIN = "org.apache.logging.log4j2";
 
- private static final String PROPERTY_DISABLE_JMX = "log4j2.disable.jmx";
  private static final String PROPERTY_ASYNC_NOTIF = "log4j2.jmx.notify.async";
  private static final String THREAD_NAME_PREFIX = "jmx.notif";
  private static final StatusLogger LOGGER = StatusLogger.getLogger();
@@ -126,10 +127,6 @@ public static String escape(final String name) {
  return sb.toString();
  }
 
- private static boolean isJmxDisabled() {
- return PropertiesUtil.getProperties().getBooleanProperty(PROPERTY_DISABLE_JMX, true);
- }
-
  public static void reregisterMBeansAfterReconfigure() {
  // avoid creating Platform MBean Server if JMX disabled
  if (isJmxDisabled()) {

log4j-core/src/main/java/org/apache/logging/log4j/core/jmx/internal/JmxUtil.java

@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you 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
+ *
+ * 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.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.logging.log4j.core.jmx.internal;
+
+import org.apache.logging.log4j.util.PropertiesUtil;
+
+// WARNING!
+// This class must be free of any dependencies to the `java.management` module!
+// Otherwise, `isJmxDisabled()` call sites would unnecessarily require the `java.management` module.
+// For details, see: https:/apache/logging-log4j2/issues/2774
+
+public final class JmxUtil {
+
+ public static boolean isJmxDisabled() {
+ return PropertiesUtil.getProperties().getBooleanProperty("log4j2.disable.jmx", true);
+ }
+
+ private JmxUtil() {}
+}

src/changelog/.2.x.x/fix_jmx_module_dep.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xmlns="https://logging.apache.org/xml/ns"
+ xsi:schemaLocation="https://logging.apache.org/xml/ns https://logging.apache.org/xml/ns/log4j-changelog-0.xsd"
+ type="fixed">
+ <issue id="2775" link="https:/apache/logging-log4j2/pull/2775"/>
+ <description format="asciidoc">Fix requirement on the `java.management` module when JMX is disabled, which is the default</description>
+</entry>