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.util;

import java.util.ArrayList;
import java.util.List;

public enum ExtensionLanguageMapping {
    JS("js", "JavaScript"), JAVASCRIPT("javascript", "JavaScript"), GVY("gvy", "Groovy"),
    GROOVY("groovy", "Groovy"), BSH("bsh", "beanshell"), BEANSHELL("beanshell", "beanshell"),
    JY("jy", "jython"), JYTHON("jython", "jython"), FTL("ftl", "freemarker"),
    FREEMARKER("freemarker", "freemarker"), VM("vm", "velocity"), VELOCITY("velocity", "velocity"),
    AWK("awk", "awk"), EJS("ejs", "ejs"), TCL("tcl", "tcl"), HS("hs", "jaskell"), JELLY("jelly", "jelly"),
    JEP("jep", "jep"), JEXL("jexl", "jexl"), JEXL2("jexl2", "jexl2"),
    RB("rb", "ruby"), RUBY("ruby", "ruby"), JUDO("judo", "judo"), JUDI("judi", "judo"), SCALA("scala", "scala"),
    CLJ("clj", "Clojure");

    private final String extension;
    private final String language;

    ExtensionLanguageMapping(final String extension, final String language) {
        this.extension = extension;
        this.language = language;

    public String getExtension() {
        return this.extension;

    public String getLanguage() {
        return this.language;

    public static ExtensionLanguageMapping getByExtension(final String extension) {
        for (final ExtensionLanguageMapping mapping : values()) {
            if (mapping.extension.equals(extension)) {
                return mapping;
        return null;

    public static List<ExtensionLanguageMapping> getByLanguage(final String language) {
        final List<ExtensionLanguageMapping> list = new ArrayList<>();
        for (final ExtensionLanguageMapping mapping : values()) {
            if (mapping.language.equals(language)) {
        return list;




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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