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 apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.

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

⏎ org/apache/logging/log4j/core/async/DefaultAsyncQueueFullPolicy.java

/*
 * 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.async;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.util.Log4jThread;

/**
 * Default router: enqueue the event for asynchronous logging in the background thread, unless the current thread is the
 * background thread and the queue is full (enqueueing would cause a deadlock). In that case send the event directly to
 * the appender (in the current thread).
 */
public class DefaultAsyncQueueFullPolicy implements AsyncQueueFullPolicy {
    @Override
    public EventRoute getRoute(final long backgroundThreadId, final Level level) {

        // LOG4J2-471: prevent deadlock when RingBuffer is full and object
        // being logged calls Logger.log() from its toString() method
        Thread currentThread = Thread.currentThread();
        if (currentThread.getId() == backgroundThreadId
                // Threads owned by log4j are most likely to result in
                // deadlocks because they generally consume events.
                // This prevents deadlocks between AsyncLoggerContext
                // disruptors.
                || currentThread instanceof Log4jThread) {
            return EventRoute.SYNCHRONOUS;
        }
        return EventRoute.ENQUEUE;
    }
}

⏎ org/apache/logging/log4j/core/async/DefaultAsyncQueueFullPolicy.java

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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