apache · ppkarwasz · Oct 22, 2024 · Sep 9, 2024
diff --git a/jul-to-log4j/pom.xml b/jul-to-log4j/pom.xml
@@ -0,0 +1,133 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ 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.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.apache.logging.log4j</groupId>
+    <artifactId>log4j</artifactId>
+    <version>${revision}</version>
+    <relativePath>../log4j-parent</relativePath>
+  </parent>
+
+  <artifactId>jul-to-log4j</artifactId>
+  <name>Apache Log4j JUL LogManager</name>
+  <description>A `java.util.logging` LogManager that forwards events to the Log4j API.</description>
+
+  <properties>
+    <!--
+      ~ OSGi and JPMS options
+      -->
+    <bnd-extra-package-options>
+      <!-- Optional annotations -->
+      org.jspecify.*;resolution:=optional
+    </bnd-extra-package-options>
+    <bnd-extra-module-options>
+      <!-- Optional modules can not be `transitive` -->
+      org.jspecify;transitive=false
+    </bnd-extra-module-options>
+  </properties>
+
+  <dependencies>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-api</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-kit</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>org.assertj</groupId>
+      <artifactId>assertj-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.hamcrest</groupId>
+      <artifactId>hamcrest</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-async-logger</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-core-test</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <configuration>
+          <systemPropertyVariables>
+            <java.awt.headless>true</java.awt.headless>
+          </systemPropertyVariables>
+          <argLine>-Xms256m -Xmx1024m</argLine>
+          <forkCount>1</forkCount>
+          <reuseForks>false</reuseForks>
+        </configuration>
+        <dependencies>
+          <!-- The `surefire-junit-platform` provider initializes JUL before tests start -->
+          <dependency>
+            <groupId>org.apache.maven.surefire</groupId>
+            <artifactId>surefire-junit47</artifactId>
+            <version>${surefire.version}</version>
+          </dependency>
+        </dependencies>
+        <executions>
+          <execution>
+            <id>default-test</id>
+            <goals>
+              <goal>test</goal>
+            </goals>
+            <phase>test</phase>
+            <configuration>
+              <!-- Use custom `j.u.l.LogManager` -->
+              <systemPropertyVariables>
+                <java.util.logging.manager>org.apache.logging.jul.tolog4j.LogManager</java.util.logging.manager>
+              </systemPropertyVariables>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>
diff --git a/...he/logging/log4j/jul/LevelTranslator.java → .../logging/jul/tolog4j/LevelTranslator.java b/...he/logging/log4j/jul/LevelTranslator.java → .../logging/jul/tolog4j/LevelTranslator.java
@@ -14,8 +14,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.jul;
+package org.apache.logging.jul.tolog4j;
 
+import org.apache.logging.jul.tolog4j.internal.DefaultLevelConverter;
+import org.apache.logging.jul.tolog4j.internal.JulProperties;
+import org.apache.logging.jul.tolog4j.spi.LevelConverter;
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.kit.env.PropertyEnvironment;

diff --git a/.../apache/logging/log4j/jul/LogManager.java → ...pache/logging/jul/tolog4j/LogManager.java b/.../apache/logging/log4j/jul/LogManager.java → ...pache/logging/jul/tolog4j/LogManager.java
@@ -14,36 +14,40 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.jul;
+package org.apache.logging.jul.tolog4j;
 
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.logging.Logger;
-import org.apache.logging.log4j.LoggingException;
+import org.apache.logging.jul.tolog4j.internal.ApiLoggerAdapter;
+import org.apache.logging.jul.tolog4j.internal.JulProperties;
+import org.apache.logging.jul.tolog4j.internal.NoOpLogger;
+import org.apache.logging.jul.tolog4j.spi.AbstractLoggerAdapter;
 import org.apache.logging.log4j.kit.env.PropertyEnvironment;
 import org.apache.logging.log4j.status.StatusLogger;
 import org.apache.logging.log4j.util.LoaderUtil;
 
 /**
- * Log4j implementation of {@link java.util.logging.LogManager}. Note that the system property
- * {@code java.util.logging.manager} must be set to {@code org.apache.logging.log4j.jul.LogManager} in order to use
- * this adaptor. This LogManager requires the {@code log4j-api} library to be available. If {@code log4j-core} is
- * also available, then more features of {@link java.util.logging.Logger} are supported.
- *
- * <p>To override the default {@link AbstractLoggerAdapter} that is used, specify the Log4j property
- * {@code log4j.jul.LoggerAdapter} and set it to the fully qualified class name of a custom
- * implementation. All implementations must have a default constructor.</p>
+ * Log4j implementation of {@link java.util.logging.LogManager}.
+ * <p>
+ *      Note that the system property {@code java.util.logging.manager} must be set to
+ *      {@code org.apache.logging.jul.tolog4j.LogManager} in order to use this adaptor.
+ *      This LogManager requires the {@code log4j-api} library to be available.
+ * </p>
+ * <p>
+ *     To override the default {@link AbstractLoggerAdapter} that is used, specify the Log4j property
+ *     {@code log4j.jul.LoggerAdapter} and set it to the fully qualified class name of a custom
+ *     implementation.
+ *     All implementations must have a default constructor.
+ * </p>
  *
  * @since 2.1
  */
 public class LogManager extends java.util.logging.LogManager {
 
     private static final org.apache.logging.log4j.Logger LOGGER = StatusLogger.getLogger();
-    private static final String CORE_LOGGER_CLASS_NAME = "org.apache.logging.log4j.core.Logger";
-    private static final String CORE_LOGGER_ADAPTER_CLASS_NAME = "org.apache.logging.log4j.jul.CoreLoggerAdapter";
-    private static final String API_LOGGER_ADAPTER_CLASS_NAME = "org.apache.logging.log4j.jul.ApiLoggerAdapter";
     private final AbstractLoggerAdapter loggerAdapter;
     // Contains the set of logger names that are actively being requested using getLogger.
     private final ThreadLocal<Set<String>> recursive = ThreadLocal.withInitial(HashSet::new);
@@ -62,21 +66,9 @@ public LogManager() {
             }
         }
         if (adapter == null) {
-            // default adapter
-            String adapterClassName;
-            try {
-                // find out if log4j-core is available
-                LoaderUtil.loadClass(CORE_LOGGER_CLASS_NAME);
-                adapterClassName = CORE_LOGGER_ADAPTER_CLASS_NAME;
-            } catch (final ClassNotFoundException ignored) {
-                adapterClassName = API_LOGGER_ADAPTER_CLASS_NAME;
-            }
-            LOGGER.debug("Attempting to use {}", adapterClassName);
-            try {
-                adapter = LoaderUtil.newCheckedInstanceOf(adapterClassName, AbstractLoggerAdapter.class);
-            } catch (final Exception e) {
-                throw LOGGER.throwing(new LoggingException(e));
-            }
+            // Use API by default
+            // See https://github.com/apache/logging-log4j2/issues/2353
+            adapter = new ApiLoggerAdapter();
         }
         loggerAdapter = adapter;
         LOGGER.info("Registered Log4j as the java.util.logging.LogManager.");

diff --git a/jul-to-log4j/src/main/java/org/apache/logging/jul/tolog4j/internal/ApiLogger.java b/jul-to-log4j/src/main/java/org/apache/logging/jul/tolog4j/internal/ApiLogger.java
@@ -0,0 +1,74 @@
+/*
+ * 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.jul.tolog4j.internal;
+
+import java.util.logging.Filter;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import org.apache.logging.jul.tolog4j.support.AbstractLogger;
+import org.apache.logging.log4j.spi.ExtendedLogger;
+import org.apache.logging.log4j.status.StatusLogger;
+
+/**
+ * Implementation of {@link java.util.logging.Logger} that ignores all method calls that do not have an equivalent in
+ * the Log4j API.
+ */
+public class ApiLogger extends AbstractLogger {
+
+    private static final String MUTATOR_DISABLED =
+            """
+            Ignoring call to `j.ul.Logger.{}()`, since the Log4j API does not provide methods to modify the underlying implementation.
+            To modify the configuration using JUL, use an `AbstractLoggerAdapter` appropriate for your logging implementation.
+            See https://logging.apache.org/log4j/3.x/log4j-jul.html#log4j.jul.loggerAdapter for more information.""";
+    private static final org.apache.logging.log4j.Logger LOGGER = StatusLogger.getLogger();
+
+    public ApiLogger(ExtendedLogger logger) {
+        super(logger);
+    }
+
+    @Override
+    public void setFilter(Filter newFilter) throws SecurityException {
+        LOGGER.warn(MUTATOR_DISABLED, "setFilter");
+    }
+
+    @Override
+    public void setLevel(Level newLevel) throws SecurityException {
+        LOGGER.warn(MUTATOR_DISABLED, "setLevel");
+    }
+
+    @Override
+    public void addHandler(Handler handler) throws SecurityException {
+        LOGGER.warn(MUTATOR_DISABLED, "addHandler");
+    }
+
+    @Override
+    public void removeHandler(Handler handler) throws SecurityException {
+        LOGGER.warn(MUTATOR_DISABLED, "removeHandler");
+    }
+
+    @Override
+    public void setUseParentHandlers(boolean useParentHandlers) {
+        LOGGER.warn(MUTATOR_DISABLED, "setUseParentHandlers");
+    }
+
+    @Override
+    public void setParent(Logger parent) {
+        throw new UnsupportedOperationException(
+                ApiLogger.class.getSimpleName() + " does not support `j.u.l.Logger#setParent()`.");
+    }
+}
diff --git a/...e/logging/log4j/jul/ApiLoggerAdapter.java → ...ul/tolog4j/internal/ApiLoggerAdapter.java b/...e/logging/log4j/jul/ApiLoggerAdapter.java → ...ul/tolog4j/internal/ApiLoggerAdapter.java
@@ -14,9 +14,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.jul;
+package org.apache.logging.jul.tolog4j.internal;
 
 import java.util.logging.Logger;
+import org.apache.logging.jul.tolog4j.spi.AbstractLoggerAdapter;
 import org.apache.logging.log4j.message.MessageFactory;
 import org.apache.logging.log4j.message.MessageFormatMessageFactory;
 import org.apache.logging.log4j.spi.LoggerContext;
@@ -32,7 +33,7 @@ public class ApiLoggerAdapter extends AbstractLoggerAdapter {
     private static final MessageFactory MESSAGE_FACTORY = new MessageFormatMessageFactory();
 
     @Override
-    protected Logger newLogger(final String name, final LoggerContext context) {
+    public Logger newLogger(final String name, final LoggerContext context) {
         return new ApiLogger(context.getLogger(name, MESSAGE_FACTORY));
     }
 }
diff --git a/...ging/log4j/jul/DefaultLevelConverter.java → ...log4j/internal/DefaultLevelConverter.java b/...ging/log4j/jul/DefaultLevelConverter.java → ...log4j/internal/DefaultLevelConverter.java
@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.jul;
+package org.apache.logging.jul.tolog4j.internal;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -24,6 +24,8 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import org.apache.logging.jul.tolog4j.LevelTranslator;
+import org.apache.logging.jul.tolog4j.spi.LevelConverter;
 import org.apache.logging.log4j.Level;
 
 /**

diff --git a/...ache/logging/log4j/jul/JulProperties.java → ...g/jul/tolog4j/internal/JulProperties.java b/...ache/logging/log4j/jul/JulProperties.java → ...g/jul/tolog4j/internal/JulProperties.java
@@ -14,8 +14,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.jul;
+package org.apache.logging.jul.tolog4j.internal;
 
+import org.apache.logging.jul.tolog4j.spi.AbstractLoggerAdapter;
+import org.apache.logging.jul.tolog4j.spi.LevelConverter;
 import org.apache.logging.log4j.kit.env.Log4jProperty;
 import org.jspecify.annotations.Nullable;
 

diff --git a/.../apache/logging/log4j/jul/NoOpLogger.java → ...ging/jul/tolog4j/internal/NoOpLogger.java b/.../apache/logging/log4j/jul/NoOpLogger.java → ...ging/jul/tolog4j/internal/NoOpLogger.java
@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.jul;
+package org.apache.logging.jul.tolog4j.internal;
 
 import java.util.ResourceBundle;
 import java.util.function.Supplier;
@@ -27,7 +27,7 @@
  */
 public class NoOpLogger extends Logger {
 
-    protected NoOpLogger(final String name) {
+    public NoOpLogger(final String name) {
         super(name, null);
     }
 

diff --git a/jul-to-log4j/src/main/java/org/apache/logging/jul/tolog4j/package-info.java b/jul-to-log4j/src/main/java/org/apache/logging/jul/tolog4j/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * 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.
+ */
+@Export
+@Version("3.0.0")
+package org.apache.logging.jul.tolog4j;
+
+import org.osgi.annotation.bundle.Export;
+import org.osgi.annotation.versioning.Version;