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/spi/ThrowableInformation.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.spi;

import org.apache.log4j.Category;
import org.apache.log4j.DefaultThrowableRenderer;

/**
  * ThrowableInformation is log4j's internal representation of
  * throwables. It essentially consists of a string array, called
  * 'rep', where the first element, that is rep[0], represents the
  * string representation of the throwable (i.e. the value you get
  * when you do throwable.toString()) and subsequent elements
  * correspond the stack trace with the top most entry of the stack
  * corresponding to the second entry of the 'rep' array that is
  * rep[1].
  *
  * @author Ceki Gülcü
  *
  * */
public class ThrowableInformation implements java.io.Serializable {

  static final long serialVersionUID = -4748765566864322735L;

  private transient Throwable throwable;
  private transient Category category;
  private String[] rep;

  public
  ThrowableInformation(Throwable throwable) {
    this.throwable = throwable;
  }

    /**
     * Create a new instance.
     * @param throwable throwable, may not be null.
     * @param category category used to obtain ThrowableRenderer, may be null.
     * @since 1.2.16
     */
  public ThrowableInformation(Throwable throwable, Category category) {
      this.throwable = throwable;
      this.category = category;
  }

    /**
     * Create new instance.
     * @since 1.2.15
     * @param r String representation of throwable.
     */
  public ThrowableInformation(final String[] r) {
      if (r != null) {
        rep = (String[]) r.clone();
      }
  }


  public
  Throwable getThrowable() {
    return throwable;
  }

  public synchronized String[] getThrowableStrRep() {
    if(rep == null) {
      ThrowableRenderer renderer = null;
      if (category != null) {
          LoggerRepository repo = category.getLoggerRepository();
          if (repo instanceof ThrowableRendererSupport) {
              renderer = ((ThrowableRendererSupport) repo).getThrowableRenderer();
          }
      }
      if (renderer == null) {
          rep = DefaultThrowableRenderer.render(throwable);
      } else {
          rep = renderer.doRender(throwable);
      }
    }
    return (String[]) rep.clone();
  }
}

⏎ org/apache/log4j/spi/ThrowableInformation.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