Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API 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 Core Implementation 2.14.1 below.

⏎ org/apache/logging/log4j/core/LifeCycle.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.logging.log4j.core;

/**
 * All proper Java frameworks implement some sort of object life cycle. In Log4j, the main interface for handling
 * the life cycle context of an object is this one. An object first starts in the {@link State#INITIALIZED} state
 * by default to indicate the class has been loaded. From here, calling the {@link #start()} method will change this
 * state to {@link State#STARTING}. After successfully being started, this state is changed to {@link State#STARTED}.
 * When the {@link #stop()} is called, this goes into the {@link State#STOPPING} state. After successfully being
 * stopped, this goes into the {@link State#STOPPED} state. In most circumstances, implementation classes should
 * store their {@link State} in a {@code volatile} field or inside an
 * {@link java.util.concurrent.atomic.AtomicReference} dependent on synchronization and concurrency requirements.
 *
 * @see AbstractLifeCycle
 */
public interface LifeCycle {

    /**
     * Status of a life cycle like a {@link LoggerContext}.
     */
    enum State {
        /** Object is in its initial state and not yet initialized. */
        INITIALIZING,
        /** Initialized but not yet started. */
        INITIALIZED,
        /** In the process of starting. */
        STARTING,
        /** Has started. */
        STARTED,
        /** Stopping is in progress. */
        STOPPING,
        /** Has stopped. */
        STOPPED
    }

    /**
     * Gets the life-cycle state.
     *
     * @return the life-cycle state
     */
    State getState();

    void initialize();

    void start();

    void stop();

    boolean isStarted();

    boolean isStopped();

}

⏎ org/apache/logging/log4j/core/LifeCycle.java

Or download all of them as a single archive file:

File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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