Source Code for Apache Log4j 1.2 Bridge

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 and source package like 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.



 * 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
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the license for the specific language governing permissions and
 * limitations under the license.

import org.apache.log4j.bridge.FilterAdapter;
import org.apache.log4j.bridge.FilterWrapper;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.Filter;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.filter.CompositeFilter;
import org.apache.logging.log4j.core.filter.ThresholdFilter;
import org.apache.logging.log4j.status.StatusLogger;

import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

 * Base class for Log4j 1 component builders.
public abstract class AbstractBuilder {

    private static Logger LOGGER = StatusLogger.getLogger();
    protected static final String FILE_PARAM = "File";
    protected static final String APPEND_PARAM = "Append";
    protected static final String BUFFERED_IO_PARAM = "BufferedIO";
    protected static final String BUFFER_SIZE_PARAM = "BufferSize";
    protected static final String MAX_SIZE_PARAM = "MaxFileSize";
    protected static final String MAX_BACKUP_INDEX = "MaxBackupIndex";
    protected static final String RELATIVE = "RELATIVE";

    private final String prefix;
    private final Properties props;

    public AbstractBuilder() {
        this.prefix = null;
        this.props = new Properties();

    public AbstractBuilder(String prefix, Properties props) {
        this.prefix = prefix + ".";
        this.props = props;

    public String getProperty(String key) {
        return props.getProperty(prefix + key);

    public String getProperty(String key, String defaultValue) {
        return props.getProperty(prefix + key, defaultValue);

    public boolean getBooleanProperty(String key) {
        return Boolean.parseBoolean(props.getProperty(prefix + key, Boolean.FALSE.toString()));

    public int getIntegerProperty(String key, int defaultValue) {
        String value = props.getProperty(key);
        try {
            if (value != null) {
                return Integer.parseInt(value);
        } catch (Exception ex) {
            LOGGER.warn("Error converting value {} of {} to an integer: {}", value, key, ex.getMessage());
        return defaultValue;

    public Properties getProperties() {
        return props;

    protected org.apache.logging.log4j.core.Filter buildFilters(String level, Filter filter) {
        if (level != null && filter != null) {
            List<org.apache.logging.log4j.core.Filter> filterList = new ArrayList<>();
            org.apache.logging.log4j.core.Filter thresholdFilter =
                    ThresholdFilter.createFilter(OptionConverter.convertLevel(level, Level.TRACE),
            Filter f = filter;
            while (f != null) {
                if (filter instanceof FilterWrapper) {
                    filterList.add(((FilterWrapper) f).getFilter());
                } else {
                    filterList.add(new FilterAdapter(f));
                f =;
            return CompositeFilter.createFilters(filterList.toArray(new org.apache.logging.log4j.core.Filter[0]));
        } else if (level != null) {
            return ThresholdFilter.createFilter(OptionConverter.convertLevel(level, Level.TRACE),
        } else if (filter != null) {
            if (filter instanceof FilterWrapper) {
                return ((FilterWrapper) filter).getFilter();
            return new FilterAdapter(filter);
        return null;



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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