Apache Log4j provides the interface that applications should code to and provides the adapter components required for implementers to create a logging implementation.

Bytecode (Java 1.4) for Apache Log4j is provided in a JAR file like log4j-1.2.17.jar.

Source Code files for Apache Log4j are provided in both binary packge like log4j-1.2.17.zip and source package like log4j-1.2.17-sources.zip. You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j 1.2.17 below.

⏎ org/apache/log4j/net/SimpleSocketServer.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.net;

import java.net.ServerSocket;
import java.net.Socket;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.xml.DOMConfigurator;


/**
 *  A simple {@link SocketNode} based server.
 *
   <pre>
   <b>Usage:</b> java org.apache.log4j.net.SimpleSocketServer port configFile

   where <em>port</em> is a part number where the server listens and
   <em>configFile</em> is a configuration file fed to the {@link
   PropertyConfigurator} or to {@link DOMConfigurator} if an XML file.
   </pre>
  *
  * @author  Ceki G&uuml;lc&uuml;
  *
  *  @since 0.8.4 
  * */
public class SimpleSocketServer  {

  static Logger cat = Logger.getLogger(SimpleSocketServer.class);

  static int port;

  public
  static
  void main(String argv[]) {
    if(argv.length == 2) {
      init(argv[0], argv[1]);
    } else {
      usage("Wrong number of arguments.");
    }
    
    try {
      cat.info("Listening on port " + port);
      ServerSocket serverSocket = new ServerSocket(port);
      while(true) {
	cat.info("Waiting to accept a new client.");
	Socket socket = serverSocket.accept();
	cat.info("Connected to client at " + socket.getInetAddress());
	cat.info("Starting new socket node.");
	new Thread(new SocketNode(socket,
				  LogManager.getLoggerRepository()),"SimpleSocketServer-" + port).start();
      }
    } catch(Exception e) {
      e.printStackTrace();
    }
  }


  static void  usage(String msg) {
    System.err.println(msg);
    System.err.println(
      "Usage: java " +SimpleSocketServer.class.getName() + " port configFile");
    System.exit(1);
  }

  static void init(String portStr, String configFile) {
    try {
      port = Integer.parseInt(portStr);
    } catch(java.lang.NumberFormatException e) {
      e.printStackTrace();
      usage("Could not interpret port number ["+ portStr +"].");
    }
   
    if(configFile.endsWith(".xml")) {
      DOMConfigurator.configure(configFile);
    } else {
      PropertyConfigurator.configure(configFile);
    }
  }
}

⏎ org/apache/log4j/net/SimpleSocketServer.java

Or download all of them as a single archive file:

File name: log4j-1.2.17-sources.jar
File size: 481200 bytes
Release date: 2012-05-06
Download 

⇒ Download and Install apache-log4j-1.2.15.zip

⇐ Download and Install log4j-1.2.17.zip

⇑ Downloading Apache Log4j 1.x JAR Packages

⇑⇑ FAQ for Apache Log4j