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.appender.rolling.DefaultRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.DirectFileRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.DirectWriteRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.RollingRandomAccessFileManager;
import org.apache.logging.log4j.core.appender.rolling.RolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.TriggeringPolicy;
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.config.plugins.PluginElement;
import org.apache.logging.log4j.core.util.Booleans;
import org.apache.logging.log4j.core.util.Integers;

 * An appender that writes to random access files and can roll over at
 * intervals.
@Plugin(name = "RollingRandomAccessFile", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
public final class RollingRandomAccessFileAppender extends AbstractOutputStreamAppender<RollingRandomAccessFileManager> {

    public static class Builder<B extends Builder<B>> extends AbstractOutputStreamAppender.Builder<B>
            implements org.apache.logging.log4j.core.util.Builder<RollingRandomAccessFileAppender> {

        public Builder() {

        private String fileName;

        private String filePattern;

        private boolean append = true;

        private TriggeringPolicy policy;

        private RolloverStrategy strategy;

        private boolean advertise;

        private String advertiseURI;

        private String filePermissions;

        private String fileOwner;

        private String fileGroup;

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

            if (strategy == null) {
                if (fileName != null) {
                    strategy = DefaultRolloverStrategy.newBuilder()
                } else {
                    strategy = DirectWriteRolloverStrategy.newBuilder()
            } else if (fileName == null && !(strategy instanceof DirectFileRolloverStrategy)) {
                LOGGER.error("RollingFileAppender '{}': When no file name is provided a DirectFileRolloverStrategy must be configured");
                return null;

            if (filePattern == null) {
                LOGGER.error("No filename pattern provided for FileAppender with name " + name);
                return null;

            if (policy == null) {
                LOGGER.error("A TriggeringPolicy must be provided");
                return null;

            final Layout<? extends Serializable> layout = getOrCreateLayout();

            final boolean immediateFlush = isImmediateFlush();
            final int bufferSize = getBufferSize();
            final RollingRandomAccessFileManager manager = RollingRandomAccessFileManager
                    .getRollingRandomAccessFileManager(fileName, filePattern, append, immediateFlush, bufferSize, policy,
                            strategy, advertiseURI, layout,
                            filePermissions, fileOwner, fileGroup, getConfiguration());
            if (manager == null) {
                return null;


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

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

        public B withFilePattern(final String filePattern) {
            this.filePattern = filePattern;
            return asBuilder();

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

        public B withPolicy(final TriggeringPolicy policy) {
            this.policy = policy;
            return asBuilder();

        public B withStrategy(final RolloverStrategy strategy) {
            this.strategy = strategy;
            return asBuilder();

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

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

        public B withFilePermissions(final String filePermissions) {
            this.filePermissions = filePermissions;
            return asBuilder();

        public B withFileOwner(final String fileOwner) {
            this.fileOwner = fileOwner;
            return asBuilder();

        public B withFileGroup(final String fileGroup) {
            this.fileGroup = fileGroup;
            return asBuilder();


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

    private RollingRandomAccessFileAppender(final String name, final Layout<? extends Serializable> layout,
            final Filter filter, final RollingRandomAccessFileManager manager, final String fileName,
            final String filePattern, final boolean ignoreExceptions, final boolean immediateFlush,
            final int bufferSize, final Advertiser advertiser, final Property[] properties) {
        super(name, layout, filter, ignoreExceptions, immediateFlush, properties, manager);
        if (advertiser != null) {
            final Map<String, String> configuration = new HashMap<>(layout.getContentFormat());
            configuration.put("contentType", layout.getContentType());
            configuration.put("name", name);
            advertisement = advertiser.advertise(configuration);
        } else {
            advertisement = null;
        this.fileName = fileName;
        this.filePattern = filePattern;
        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) {
        final RollingRandomAccessFileManager manager = getManager();

        // 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.
        manager.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 for the Appender.
     * @return The file name.
    public String getFileName() {
        return fileName;

     * Returns the file pattern used when rolling over.
     * @return The file pattern.
    public String getFilePattern() {
        return filePattern;

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

     * Create a RollingRandomAccessFileAppender.
     * @param fileName The name of the file that is actively written to.
     *            (required).
     * @param filePattern The pattern of the file name to use on rollover.
     *            (required).
     * @param append If true, events are appended to the file. If false, the
     *            file is overwritten when opened. Defaults to "true"
     * @param name The name of the Appender (required).
     * @param immediateFlush When true, events are immediately flushed. Defaults
     *            to "true".
     * @param bufferSizeStr The buffer size, defaults to {@value RollingRandomAccessFileManager#DEFAULT_BUFFER_SIZE}.
     * @param policy The triggering policy. (required).
     * @param strategy The rollover strategy. Defaults to
     *            DefaultRolloverStrategy.
     * @param layout The layout to use (defaults to the default PatternLayout).
     * @param filter The Filter or null.
     * @param ignoreExceptions If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise
     *               they are propagated to the caller.
     * @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 A RollingRandomAccessFileAppender.
     * @deprecated Use {@link #newBuilder()}.
    public static <B extends Builder<B>> RollingRandomAccessFileAppender createAppender(
            final String fileName,
            final String filePattern,
            final String append,
            final String name,
            final String immediateFlush,
            final String bufferSizeStr,
            final TriggeringPolicy policy,
            final RolloverStrategy strategy,
            final Layout<? extends Serializable> layout,
            final Filter filter,
            final String ignoreExceptions,
            final String advertise,
            final String advertiseURI,
            final Configuration configuration) {

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

        return RollingRandomAccessFileAppender.<B>newBuilder()

    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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