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.appender;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
import org.apache.logging.log4j.core.util.Booleans;
import org.apache.logging.log4j.core.util.Integers;

 * File Appender.
@Plugin(name = "RandomAccessFile", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
public final class RandomAccessFileAppender extends AbstractOutputStreamAppender<RandomAccessFileManager> {

     * Builds RandomAccessFileAppender instances.
     * @param <B>
     *            The type to build
    public static class Builder<B extends Builder<B>> extends AbstractOutputStreamAppender.Builder<B>
            implements org.apache.logging.log4j.core.util.Builder<RandomAccessFileAppender> {

        private String fileName;

        private boolean append = true;

        private boolean advertise;

        private String advertiseURI;

        public RandomAccessFileAppender build() {
            final String name = getName();
            if (name == null) {
                LOGGER.error("No name provided for FileAppender");
                return null;

            if (fileName == null) {
                LOGGER.error("No filename provided for FileAppender with name " + name);
                return null;
            final Layout<? extends Serializable> layout = getOrCreateLayout();
            final boolean immediateFlush = isImmediateFlush();
            final RandomAccessFileManager manager = RandomAccessFileManager.getFileManager(fileName, append,
                    immediateFlush, getBufferSize(), advertiseURI, layout, null);
            if (manager == null) {
                return null;

            return new RandomAccessFileAppender(name, layout, getFilter(), manager, fileName, isIgnoreExceptions(),
                    immediateFlush, advertise ? getConfiguration().getAdvertiser() : null, getPropertyArray());

        public B setFileName(final String fileName) {
            this.fileName = fileName;
            return asBuilder();

        public B setAppend(final boolean append) {
            this.append = append;
            return asBuilder();

        public B setAdvertise(final boolean advertise) {
            this.advertise = advertise;
            return asBuilder();

        public B setAdvertiseURI(final String advertiseURI) {
            this.advertiseURI = advertiseURI;
            return asBuilder();


    private final String fileName;
    private Object advertisement;
    private final Advertiser advertiser;

    private RandomAccessFileAppender(final String name, final Layout<? extends Serializable> layout,
            final Filter filter, final RandomAccessFileManager manager, final String filename,
            final boolean ignoreExceptions, final boolean immediateFlush, final Advertiser advertiser,
            final Property[] properties) {

        super(name, layout, filter, ignoreExceptions, immediateFlush, properties, manager);
        if (advertiser != null) {
            final Map<String, String> configuration = new HashMap<>(
            configuration.put("contentType", layout.getContentType());
            configuration.put("name", name);
            advertisement = advertiser.advertise(configuration);
        this.fileName = filename;
        this.advertiser = advertiser;

    public boolean stop(final long timeout, final TimeUnit timeUnit) {
        super.stop(timeout, timeUnit, false);
        if (advertiser != null) {
        return true;

     * Write the log entry rolling over the file when required.
     * @param event The LogEvent.
    public void append(final LogEvent event) {

        // Leverage the nice batching behaviour of async Loggers/Appenders:
        // we can signal the file manager that it needs to flush the buffer
        // to disk at the end of a batch.
        // From a user's point of view, this means that all log events are
        // _always_ available in the log file, without incurring the overhead
        // of immediateFlush=true.
        getManager().setEndOfBatch(event.isEndOfBatch()); // FIXME manager's EndOfBatch threadlocal can be deleted

        // LOG4J2-1292 utilize gc-free Layout.encode() method: taken care of in superclass

     * Returns the file name this appender is associated with.
     * @return The File name.
    public String getFileName() {
        return this.fileName;

     * Returns the size of the file manager's buffer.
     * @return the buffer size
    public int getBufferSize() {
        return getManager().getBufferSize();

    // difference from standard File Appender:
    // locking is not supported and buffering cannot be switched off
     * Create a File Appender.
     * @param fileName The name and path of the file.
     * @param append "True" if the file should be appended to, "false" if it
     *            should be overwritten. The default is "true".
     * @param name The name of the Appender.
     * @param immediateFlush "true" if the contents should be flushed on every
     *            write, "false" otherwise. The default is "true".
     * @param bufferSizeStr The buffer size, defaults to {@value RandomAccessFileManager#DEFAULT_BUFFER_SIZE}.
     * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise
     *               they are propagated to the caller.
     * @param layout The layout to use to format the event. If no layout is
     *            provided the default PatternLayout will be used.
     * @param filter The filter, if any, to use.
     * @param advertise "true" if the appender configuration should be
     *            advertised, "false" otherwise.
     * @param advertiseURI The advertised URI which can be used to retrieve the
     *            file contents.
     * @param configuration The Configuration.
     * @return The FileAppender.
     * @deprecated Use {@link #newBuilder()}.
    public static <B extends Builder<B>> RandomAccessFileAppender createAppender(
            final String fileName,
            final String append,
            final String name,
            final String immediateFlush,
            final String bufferSizeStr,
            final String ignore,
            final Layout<? extends Serializable> layout,
            final Filter filter,
            final String advertise,
            final String advertiseURI,
            final Configuration configuration) {

        final boolean isAppend = Booleans.parseBoolean(append, true);
        final boolean isFlush = Booleans.parseBoolean(immediateFlush, true);
        final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
        final boolean isAdvertise = Boolean.parseBoolean(advertise);
        final int bufferSize = Integers.parseInt(bufferSizeStr, RandomAccessFileManager.DEFAULT_BUFFER_SIZE);

        return RandomAccessFileAppender.<B>newBuilder()

     * Creates a builder for a RandomAccessFileAppender.
     * @return a builder for a RandomAccessFileAppender.
    public static <B extends Builder<B>> B newBuilder() {
        return new Builder<B>().asBuilder();




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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