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/helpers/OnlyOnceErrorHandler.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.helpers;

import  org.apache.log4j.spi.ErrorHandler;
import  org.apache.log4j.spi.LoggingEvent;
import  org.apache.log4j.Logger;
import  org.apache.log4j.Appender;

import java.io.InterruptedIOException;

/**

   The <code>OnlyOnceErrorHandler</code> implements log4j's default
   error handling policy which consists of emitting a message for the
   first error in an appender and ignoring all following errors.

   <p>The error message is printed on <code>System.err</code>. 

   <p>This policy aims at protecting an otherwise working application
   from being flooded with error messages when logging fails.

   @author Ceki G&uuml;lc&uuml;
   @since 0.9.0 */
public class OnlyOnceErrorHandler implements ErrorHandler {


  final String WARN_PREFIX = "log4j warning: ";
  final String ERROR_PREFIX = "log4j error: ";

  boolean firstTime = true;


  /**
     Does not do anything.
   */
  public 
  void setLogger(Logger logger) {
  }


  /**
     No options to activate.
  */
  public 
  void activateOptions() {
  }


  /**
     Prints the message and the stack trace of the exception on
     <code>System.err</code>.  */
  public
  void error(String message, Exception e, int errorCode) { 
    error(message, e, errorCode, null);
  }

  /**
     Prints the message and the stack trace of the exception on
     <code>System.err</code>.
   */
  public
  void error(String message, Exception e, int errorCode, LoggingEvent event) {
    if (e instanceof InterruptedIOException || e instanceof InterruptedException) {
        Thread.currentThread().interrupt();
    }
    if(firstTime) {
      LogLog.error(message, e);
      firstTime = false;
    }
  }


  /**
     Print a the error message passed as parameter on
     <code>System.err</code>.  
  */
  public 
  void error(String message) {
    if(firstTime) {
      LogLog.error(message);
      firstTime = false;
    }
  }
  
  /**
     Does not do anything.
   */
  public
  void setAppender(Appender appender) {
  }

  /**
     Does not do anything.
   */
  public
  void setBackupAppender(Appender appender) {
  }
}

⏎ org/apache/log4j/helpers/OnlyOnceErrorHandler.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