Source Code for Apache Log4j Core Implementation

Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API are provided in both binary packge like and source package like You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.



 * 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
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the license for the specific language governing permissions and
 * limitations under the license.
package org.apache.logging.log4j.core.async;

import org.apache.logging.log4j.core.util.Constants;
import org.apache.logging.log4j.message.AsynchronouslyFormattable;
import org.apache.logging.log4j.message.Message;

 * Helper class providing some async logging-related functionality.
 * <p>
 *     Consider this class private.
 * </p>
public class InternalAsyncUtil {
     * Returns the specified message, with its content frozen unless system property
     * {@code log4j.format.msg.async} is true or the message class is annotated with
     * {@link AsynchronouslyFormattable}.
     * @param msg the message object to inspect, modify and return
     * @return Returns the specified message, with its content frozen
    public static Message makeMessageImmutable(final Message msg) {
        // if the Message instance is reused, there is no point in freezing its message here
        if (msg != null && !canFormatMessageInBackground(msg)) {
            msg.getFormattedMessage(); // LOG4J2-763: ask message to makeMessageImmutable parameters
        return msg;

    private static boolean canFormatMessageInBackground(final Message message) {
        return Constants.FORMAT_MESSAGES_IN_BACKGROUND // LOG4J2-898: user wants to format all msgs in background
                || message.getClass().isAnnotationPresent(AsynchronouslyFormattable.class); // LOG4J2-1718



Or download all of them as a single archive file:

File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06


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