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 apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. 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.

⏎ org/apache/log4j/xml/Log4jEntityResolver.java

/*
 * 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
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j.xml;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.status.StatusLogger;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;

import java.io.ByteArrayInputStream;
import java.io.InputStream;

/**
 * An {@link EntityResolver} specifically designed to return
 * <code>log4j.dtd</code> which is embedded within the log4j jar
 * file.
 */
public class Log4jEntityResolver implements EntityResolver {
    private static final Logger LOGGER = StatusLogger.getLogger();
    private static final String PUBLIC_ID = "-//APACHE//DTD LOG4J 1.2//EN";

    @Override
    public InputSource resolveEntity(String publicId, String systemId) {
        if (systemId.endsWith("log4j.dtd") || PUBLIC_ID.equals(publicId)) {
            Class<?> clazz = getClass();
            InputStream in = clazz.getResourceAsStream("/org/apache/log4j/xml/log4j.dtd");
            if (in == null) {
                LOGGER.warn("Could not find [log4j.dtd] using [{}] class loader, parsed without DTD.",
                        clazz.getClassLoader());
                in = new ByteArrayInputStream(new byte[0]);
            }
            return new InputSource(in);
        }
        return null;
    }
}

⏎ org/apache/log4j/xml/Log4jEntityResolver.java

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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