Source Code for Apache Log4j 1.2 Bridge

Apache Log4j 1.2 Bridge allows applications coded to use Log4j 1.2 API to use Log4j 2 instead.

Bytecode (Java 8) for Apache Log4j 1.2 Bridge is provided in a separate JAR file like log4j-1.2-api-2.14.1.jar.

Source Code files for Apache Log4j 1.2 Bridge 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 1.2 Bridge 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.log4j.rewrite;

import org.apache.log4j.bridge.LogEventAdapter;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.LocationInfo;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.impl.Log4jLogEvent;
import org.apache.logging.log4j.message.MapMessage;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.SimpleMessage;
import org.apache.logging.log4j.util.SortedArrayStringMap;

import java.util.HashMap;
import java.util.Map;

 * This policy rewrites events where the message of the
 * original event implements java.util.Map.
 * All other events are passed through unmodified.
 * If the map contains a "message" entry, the value will be
 * used as the message for the rewritten event.  The rewritten
 * event will have a property set that is the combination of the
 * original property set and the other members of the message map.
 * If both the original property set and the message map
 * contain the same entry, the value from the message map
 * will overwrite the original property set.
 * <p>
 * The combination of the RewriteAppender and this policy
 * performs the same actions as the MapFilter from log4j 1.3.
 * </p>
public class MapRewritePolicy implements RewritePolicy {
     * {@inheritDoc}
    public LoggingEvent rewrite(final LoggingEvent source) {
        Object msg = source.getMessage();
        if (msg instanceof MapMessage || msg instanceof Map) {
            Map<String, String> props = source.getProperties() != null ? new HashMap<>(source.getProperties())
                    : new HashMap<>();
            Map<String, Object> eventProps = msg instanceof Map ? (Map) msg : ((MapMessage) msg).getData();
            //   if the map sent in the logging request
            //      has "message" entry, use that as the message body
            //      otherwise, use the entire map.
            Message newMessage = null;
            Object newMsg = eventProps.get("message");
            if (newMsg != null) {
                newMessage = new SimpleMessage(newMsg.toString());
                for (Map.Entry<String, Object> entry : eventProps.entrySet()) {
                    if (!("message".equals(entry.getKey()))) {
                        props.put(entry.getKey(), entry.getValue().toString());
            } else {
                return source;

            LogEvent event;
            if (source instanceof LogEventAdapter) {
                event = new Log4jLogEvent.Builder(((LogEventAdapter) source).getEvent())
                        .setContextData(new SortedArrayStringMap(props))
            } else {
                LocationInfo info = source.getLocationInformation();
                StackTraceElement element = new StackTraceElement(info.getClassName(), info.getMethodName(),
                        info.getFileName(), Integer.parseInt(info.getLineNumber()));
                Thread thread = getThread(source.getThreadName());
                long threadId = thread != null ? thread.getId() : 0;
                int threadPriority = thread != null ? thread.getPriority() : 0;
                event = Log4jLogEvent.newBuilder()
                        .setContextData(new SortedArrayStringMap(props))
            return new LogEventAdapter(event);
        return source;


    private Thread getThread(String name) {
        for (Thread thread : Thread.getAllStackTraces().keySet()) {
            if (thread.getName().equals(name)) {
                return thread;
        return null;



Or download all of them as a single archive file:

File name: log4j-1.2-api-2.14.1-sources.jar
File size: 168047 bytes
Release date: 2021-03-06


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