commons-net.jar is the bytecode of Apache Commons Net library, which implements the client side of many basic Internet protocols.

Apache Commons Net Source Code files are provided in the binary packge (commons-net-3.8.0-bin.zip). You can download it at Apache Commons Net Website.

The source code of commons-net-3.8.0.jar is provided below:

⏎ org/apache/commons/net/ftp/parser/DefaultFTPFileEntryParserFactory.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.commons.net.ftp.parser;

import java.util.regex.Pattern;

import org.apache.commons.net.ftp.Configurable;
import org.apache.commons.net.ftp.FTPClientConfig;
import org.apache.commons.net.ftp.FTPFileEntryParser;


/**
 * This is the default implementation of the
 * FTPFileEntryParserFactory interface.  This is the
 * implementation that will be used by
 * org.apache.commons.net.ftp.FTPClient.listFiles()
 * if no other implementation has been specified.
 *
 * @see org.apache.commons.net.ftp.FTPClient#listFiles
 * @see org.apache.commons.net.ftp.FTPClient#setParserFactory
 */
public class DefaultFTPFileEntryParserFactory
    implements FTPFileEntryParserFactory
{

    // Match a plain Java Identifier
    private static final String JAVA_IDENTIFIER = "\\p{javaJavaIdentifierStart}(\\p{javaJavaIdentifierPart})*";
    // Match a qualified name, e.g. a.b.c.Name - but don't allow the default package as that would allow "VMS"/"UNIX" etc.
    private static final String JAVA_QUALIFIED_NAME  = "("+JAVA_IDENTIFIER+"\\.)+"+JAVA_IDENTIFIER;
    // Create the pattern, as it will be reused many times
    private static final Pattern JAVA_QUALIFIED_NAME_PATTERN = Pattern.compile(JAVA_QUALIFIED_NAME);

    /**
     * This default implementation of the FTPFileEntryParserFactory
     * interface works according to the following logic:
     * First it attempts to interpret the supplied key as a fully
     * qualified classname (default package is not allowed) of a class implementing the
     * FTPFileEntryParser interface.  If that succeeds, a parser
     * object of this class is instantiated and is returned;
     * otherwise it attempts to interpret the key as an identirier
     * commonly used by the FTP SYST command to identify systems.
     * <p>
     * If <code>key</code> is not recognized as a fully qualified
     * classname known to the system, this method will then attempt
     * to see whether it <b>contains</b> a string identifying one of
     * the known parsers.  This comparison is <b>case-insensitive</b>.
     * The intent here is where possible, to select as keys strings
     * which are returned by the SYST command on the systems which
     * the corresponding parser successfully parses.  This enables
     * this factory to be used in the auto-detection system.
     *
     * @param key    should be a fully qualified classname corresponding to
     *               a class implementing the FTPFileEntryParser interface<br>
     *               OR<br>
     *               a string containing (case-insensitively) one of the
     *               following keywords:
     *               <ul>
     *               <li>{@link FTPClientConfig#SYST_UNIX UNIX}</li>
     *               <li>{@link FTPClientConfig#SYST_NT WINDOWS}</li>
     *               <li>{@link FTPClientConfig#SYST_OS2 OS/2}</li>
     *               <li>{@link FTPClientConfig#SYST_OS400 OS/400}</li>
     *               <li>{@link FTPClientConfig#SYST_AS400 AS/400}</li>
     *               <li>{@link FTPClientConfig#SYST_VMS VMS}</li>
     *               <li>{@link FTPClientConfig#SYST_MVS MVS}</li>
     *               <li>{@link FTPClientConfig#SYST_NETWARE NETWARE}</li>
     *               <li>{@link FTPClientConfig#SYST_L8 TYPE:L8}</li>
     *               </ul>
     * @return the FTPFileEntryParser corresponding to the supplied key.
     * @throws ParserInitializationException thrown if for any reason the factory cannot resolve
     *                   the supplied key into an FTPFileEntryParser.
     * @see FTPFileEntryParser
     */
    @Override
    public FTPFileEntryParser createFileEntryParser(final String key)
    {
        if (key == null) {
            throw new ParserInitializationException("Parser key cannot be null");
        }
        return createFileEntryParser(key, null);
    }

    // Common method to process both key and config parameters.
    private FTPFileEntryParser createFileEntryParser(final String key, final FTPClientConfig config) {
        FTPFileEntryParser parser = null;

        // Is the key a possible class name?
        if (JAVA_QUALIFIED_NAME_PATTERN.matcher(key).matches()) {
            try
            {
                final Class<?> parserClass = Class.forName(key);
                try {
                    parser = (FTPFileEntryParser) parserClass.newInstance();
                } catch (final ClassCastException e) {
                    throw new ParserInitializationException(parserClass.getName()
                        + " does not implement the interface "
                        + "org.apache.commons.net.ftp.FTPFileEntryParser.", e);
                } catch (final Exception | ExceptionInInitializerError e) {
                    throw new ParserInitializationException("Error initializing parser", e);
                }
            } catch (final ClassNotFoundException e) {
                // OK, assume it is an alias
            }
        }

        if (parser == null) { // Now try for aliases
            final String ukey = key.toUpperCase(java.util.Locale.ENGLISH);
            if (ukey.indexOf(FTPClientConfig.SYST_UNIX_TRIM_LEADING) >= 0)
            {
                parser = new UnixFTPEntryParser(config, true);
            }
            // must check this after SYST_UNIX_TRIM_LEADING as it is a substring of it
            else if (ukey.indexOf(FTPClientConfig.SYST_UNIX) >= 0)
            {
                parser = new UnixFTPEntryParser(config, false);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_VMS) >= 0)
            {
                parser = new VMSVersioningFTPEntryParser(config);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_NT) >= 0)
            {
                parser = createNTFTPEntryParser(config);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_OS2) >= 0)
            {
                parser = new OS2FTPEntryParser(config);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_OS400) >= 0 ||
                    ukey.indexOf(FTPClientConfig.SYST_AS400) >= 0)
            {
                parser = createOS400FTPEntryParser(config);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_MVS) >= 0)
            {
                parser = new MVSFTPEntryParser(); // Does not currently support config parameter
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_NETWARE) >= 0)
            {
                parser = new NetwareFTPEntryParser(config);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_MACOS_PETER) >= 0)
            {
                parser = new MacOsPeterFTPEntryParser(config);
            }
            else if (ukey.indexOf(FTPClientConfig.SYST_L8) >= 0)
            {
                // L8 normally means Unix, but move it to the end for some L8 systems that aren't.
                // This check should be last!
                parser = new UnixFTPEntryParser(config);
            }
            else
            {
                throw new ParserInitializationException("Unknown parser type: " + key);
            }
        }

        if (parser instanceof Configurable) {
            ((Configurable)parser).configure(config);
        }
        return parser;
    }

    /**
     * <p>Implementation extracts a key from the supplied
     * {@link  FTPClientConfig FTPClientConfig}
     * parameter and creates an object implementing the
     * interface FTPFileEntryParser and uses the supplied configuration
     * to configure it.
     * </p><p>
     * Note that this method will generally not be called in scenarios
     * that call for autodetection of parser type but rather, for situations
     * where the user knows that the server uses a non-default configuration
     * and knows what that configuration is.
     * </p>
     * @param config  A {@link  FTPClientConfig FTPClientConfig}
     * used to configure the parser created
     *
     * @return the @link  FTPFileEntryParser FTPFileEntryParser} so created.
     * @throws ParserInitializationException
     *                   Thrown on any exception in instantiation
     * @throws NullPointerException if {@code config} is {@code null}
     * @since 1.4
     */
    @Override
    public FTPFileEntryParser createFileEntryParser(final FTPClientConfig config)
    throws ParserInitializationException
    {
        final String key = config.getServerSystemKey();
        return createFileEntryParser(key, config);
    }


    public FTPFileEntryParser createUnixFTPEntryParser()
    {
        return new UnixFTPEntryParser();
    }

    public FTPFileEntryParser createVMSVersioningFTPEntryParser()
    {
        return new VMSVersioningFTPEntryParser();
    }

    public FTPFileEntryParser createNetwareFTPEntryParser() {
        return new NetwareFTPEntryParser();
    }

    public FTPFileEntryParser createNTFTPEntryParser()
    {
        return createNTFTPEntryParser(null);
    }

    /**
     * Creates an NT FTP parser: if the config exists, and the system key equals
     * {@link FTPClientConfig#SYST_NT} then a plain {@link NTFTPEntryParser} is used,
     * otherwise a composite of {@link NTFTPEntryParser} and {@link UnixFTPEntryParser} is used.
     * @param config the config to use, may be {@code null}
     * @return the parser
     */
    private FTPFileEntryParser createNTFTPEntryParser(final FTPClientConfig config)
    {
        if (config != null && FTPClientConfig.SYST_NT.equals(
                config.getServerSystemKey()))
        {
            return new NTFTPEntryParser(config);
        }
        // clone the config as it may be changed by the parsers (NET-602)
        final FTPClientConfig config2 =  config != null ? new FTPClientConfig(config) : null;
        return new CompositeFileEntryParser(new FTPFileEntryParser[]
               {
                   new NTFTPEntryParser(config),
                   new UnixFTPEntryParser(config2,
                           config2 != null && FTPClientConfig.SYST_UNIX_TRIM_LEADING.equals(config2.getServerSystemKey()))
               });
    }

     public FTPFileEntryParser createOS2FTPEntryParser()
    {
        return new OS2FTPEntryParser();
    }

    public FTPFileEntryParser createOS400FTPEntryParser()
    {
        return createOS400FTPEntryParser(null);
    }

    /**
     * Creates an OS400 FTP parser: if the config exists, and the system key equals
     * {@link FTPClientConfig#SYST_OS400} then a plain {@link OS400FTPEntryParser} is used,
     * otherwise a composite of {@link OS400FTPEntryParser} and {@link UnixFTPEntryParser} is used.
     * @param config the config to use, may be {@code null}
     * @return the parser
     */
    private FTPFileEntryParser createOS400FTPEntryParser(final FTPClientConfig config)
        {
        if (config != null &&
                FTPClientConfig.SYST_OS400.equals(config.getServerSystemKey()))
        {
            return new OS400FTPEntryParser(config);
        }
        // clone the config as it may be changed by the parsers (NET-602)
        final FTPClientConfig config2 =  config != null ? new FTPClientConfig(config) : null;
        return new CompositeFileEntryParser(new FTPFileEntryParser[]
            {
                new OS400FTPEntryParser(config),
                new UnixFTPEntryParser(config2,
                        config2 != null && FTPClientConfig.SYST_UNIX_TRIM_LEADING.equals(config2.getServerSystemKey()))
            });
    }

    public FTPFileEntryParser createMVSEntryParser()
    {
        return new MVSFTPEntryParser();
    }

}

⏎ org/apache/commons/net/ftp/parser/DefaultFTPFileEntryParserFactory.java

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File name: commons-net-3.8.0-sources.jar
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Release date: 2020-01-22
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