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.Objects;

import javax.script.Bindings;

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.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
import org.apache.logging.log4j.core.script.AbstractScript;
import org.apache.logging.log4j.core.script.ScriptManager;

@Plugin(name = "ScriptAppenderSelector", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
public class ScriptAppenderSelector extends AbstractAppender {

     * Builds an appender.
    public static final class Builder implements org.apache.logging.log4j.core.util.Builder<Appender> {

        private AppenderSet appenderSet;

        private Configuration configuration;

        private String name;

        private AbstractScript script;

		public Appender build() {
			if (name == null) {
				LOGGER.error("Name missing.");
				return null;
			if (script == null) {
				LOGGER.error("Script missing for ScriptAppenderSelector appender {}", name);
				return null;
			if (appenderSet == null) {
				LOGGER.error("AppenderSet missing for ScriptAppenderSelector appender {}", name);
				return null;
			if (configuration == null) {
				LOGGER.error("Configuration missing for ScriptAppenderSelector appender {}", name);
				return null;
			final ScriptManager scriptManager = configuration.getScriptManager();
			final Bindings bindings = scriptManager.createBindings(script);
			LOGGER.debug("ScriptAppenderSelector '{}' executing {} '{}': {}", name, script.getLanguage(),
					script.getName(), script.getScriptText());
			final Object object = scriptManager.execute(script.getName(), bindings);
			final String actualAppenderName = Objects.toString(object, null);
			LOGGER.debug("ScriptAppenderSelector '{}' selected '{}'", name, actualAppenderName);
			return appenderSet.createAppender(actualAppenderName, name);

        public AppenderSet getAppenderSet() {
            return appenderSet;

        public Configuration getConfiguration() {
            return configuration;

        public String getName() {
            return name;

        public AbstractScript getScript() {
            return script;

        public Builder withAppenderNodeSet(@SuppressWarnings("hiding") final AppenderSet appenderSet) {
            this.appenderSet = appenderSet;
            return this;

        public Builder withConfiguration(@SuppressWarnings("hiding") final Configuration configuration) {
            this.configuration = configuration;
            return this;

        public Builder withName(@SuppressWarnings("hiding") final String name) {
   = name;
            return this;

        public Builder withScript(@SuppressWarnings("hiding") final AbstractScript script) {
            this.script = script;
            return this;


    public static Builder newBuilder() {
        return new Builder();

    private ScriptAppenderSelector(final String name, final Filter filter, final Layout<? extends Serializable> layout,
            final Property[] properties) {
        super(name, filter, layout, true, Property.EMPTY_ARRAY);

    public void append(final LogEvent event) {
        // Do nothing: This appender is only used to discover and build another appender




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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