Source Code for Apache Log4j Web Servlet Containers

Apache Log4j Web Servlet Containers provides support for automatically enabling Log4j in Servlet containers.

Bytecode (Java 8) for Apache Log4j Web Servlet Containers is provided in a separate JAR file like log4j-web-2.14.1.jar.

Source Code files for Apache Log4j IOStreams 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 Web Servlet Containers 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.web;
// Please note that if you move this class, make sure to update the Interpolator class (if still applicable) or remove
// this comment if no longer relevant

import javax.servlet.ServletContext;

import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.lookup.AbstractLookup;
import org.apache.logging.log4j.util.Strings;

@Plugin(name = "web", category = "Lookup")
public class WebLookup extends AbstractLookup {
    private static final String ATTR_PREFIX = "attr.";
    private static final String INIT_PARAM_PREFIX = "initParam.";

    public String lookup(final LogEvent event, final String key) {
        final ServletContext ctx = WebLoggerContextUtils.getServletContext();
        if (ctx == null) {
            return null;

        if (key.startsWith(ATTR_PREFIX)) {
            final String attrName = key.substring(ATTR_PREFIX.length());
            final Object attrValue = ctx.getAttribute(attrName);
            return attrValue == null ? null : attrValue.toString();

        if (key.startsWith(INIT_PARAM_PREFIX)) {
            final String paramName = key.substring(INIT_PARAM_PREFIX.length());
            return ctx.getInitParameter(paramName);

        if ("rootDir".equals(key)) {
            final String root = ctx.getRealPath("/");
            if (root == null) {
                final String msg = "Failed to resolve web:rootDir -- " +
                        "servlet container unable to translate virtual path " +
                        " to real path (probably not deployed as exploded";
                throw new IllegalStateException(msg);
            return root;

        if ("contextPathName".equals(key)) {
            String path = ctx.getContextPath();
            if (path.trim().contains("/")) {
                String[] fields = path.split("/");
                for (String field : fields) {
                    if (field.length() > 0) {
                        return field;
                return null;
            return ctx.getContextPath();

        if ("contextPath".equals(key)) {
            return ctx.getContextPath();

        if ("servletContextName".equals(key)) {
            return ctx.getServletContextName();

        if ("serverInfo".equals(key)) {
            return ctx.getServerInfo();

        if ("effectiveMajorVersion".equals(key)) {
            return String.valueOf(ctx.getEffectiveMajorVersion());

        if ("effectiveMinorVersion".equals(key)) {
            return String.valueOf(ctx.getEffectiveMinorVersion());

        if ("majorVersion".equals(key)) {
            return String.valueOf(ctx.getMajorVersion());

        if ("minorVersion".equals(key)) {
            return String.valueOf(ctx.getMinorVersion());

        if (ctx.getAttribute(key) != null) {
            return ctx.getAttribute(key).toString();

        if (ctx.getInitParameter(key) != null) {
            return ctx.getInitParameter(key);

        ctx.log(getClass().getName() + " unable to resolve key " + Strings.quote(key));
        return null;



Or download all of them as a single archive file:

File name: log4j-web-2.14.1-sources.jar
File size: 30223 bytes
Release date: 2021-03-06


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