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.pattern;

import java.util.regex.Pattern;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.status.StatusLogger;

 * Replace tokens in the LogEvent message.
@Plugin(name = "replace", category = Core.CATEGORY_NAME, printObject = true)
public final class RegexReplacement {

    private static final Logger LOGGER = StatusLogger.getLogger();

    private final Pattern pattern;

    private final String substitution;

     * Private constructor.
     * @param pattern The Pattern.
     * @param substitution The substitution String.
    private RegexReplacement(final Pattern pattern, final String substitution) {
        this.pattern = pattern;
        this.substitution = substitution;

     * Perform the replacement.
     * @param msg The String to match against.
     * @return the replacement String.
    public String format(final String msg) {
        return pattern.matcher(msg).replaceAll(substitution);

    public String toString() {
        return "replace(regex=" + pattern.pattern() + ", replacement=" + substitution + ')';

     * Create a RegexReplacement.
     * @param regex The regular expression to locate.
     * @param replacement The replacement value.
     * @return A RegexReplacement.
    public static RegexReplacement createRegexReplacement(
            @PluginAttribute("regex") final Pattern regex,
            @PluginAttribute("replacement") final String replacement) {
        if (regex == null) {
            LOGGER.error("A regular expression is required for replacement");
            return null;
        if (replacement == null) {
            LOGGER.error("A replacement string is required to perform replacement");
        // FIXME: should we use Matcher.quoteReplacement() here?
        return new RegexReplacement(regex, replacement);




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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