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/DefaultSocketFactory.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;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;

import javax.net.SocketFactory;

/**
 * DefaultSocketFactory implements the SocketFactory interface by
 * simply wrapping the java.net.Socket and java.net.ServerSocket
 * constructors.  It is the default SocketFactory used by
 * {@link org.apache.commons.net.SocketClient}
 * implementations.
 *
 *
 * @see SocketFactory
 * @see SocketClient
 * @see SocketClient#setSocketFactory
 */

public class DefaultSocketFactory extends SocketFactory
{
    /** The proxy to use when creating new sockets. */
    private final Proxy connProxy;

    /**
     * The default constructor.
     */
    public DefaultSocketFactory()
    {
        this(null);
    }

    /**
     * A constructor for sockets with proxy support.
     *
     * @param proxy The Proxy to use when creating new Sockets.
     * @since 3.2
     */
    public DefaultSocketFactory(final Proxy proxy)
    {
        connProxy = proxy;
    }

    /**
     * Creates an unconnected Socket.
     *
     * @return A new unconnected Socket.
     * @throws IOException If an I/O error occurs while creating the Socket.
     * @since 3.2
     */
    @Override
    public Socket createSocket() throws IOException
    {
        if (connProxy != null)
        {
            return new Socket(connProxy);
        }
        return new Socket();
    }

    /**
     * Creates a Socket connected to the given host and port.
     *
     * @param host The hostname to connect to.
     * @param port The port to connect to.
     * @return A Socket connected to the given host and port.
     * @throws UnknownHostException  If the hostname cannot be resolved.
     * @throws IOException If an I/O error occurs while creating the Socket.
     */
    @Override
    public Socket createSocket(final String host, final int port)
    throws UnknownHostException, IOException
    {
        if (connProxy != null)
        {
            final Socket s = new Socket(connProxy);
            s.connect(new InetSocketAddress(host, port));
            return s;
        }
        return new Socket(host, port);
    }

    /**
     * Creates a Socket connected to the given host and port.
     *
     * @param address The address of the host to connect to.
     * @param port The port to connect to.
     * @return A Socket connected to the given host and port.
     * @throws IOException If an I/O error occurs while creating the Socket.
     */
    @Override
    public Socket createSocket(final InetAddress address, final int port)
    throws IOException
    {
        if (connProxy != null)
        {
            final Socket s = new Socket(connProxy);
            s.connect(new InetSocketAddress(address, port));
            return s;
        }
        return new Socket(address, port);
    }

    /**
     * Creates a Socket connected to the given host and port and
     * originating from the specified local address and port.
     *
     * @param host The hostname to connect to.
     * @param port The port to connect to.
     * @param localAddr  The local address to use.
     * @param localPort  The local port to use.
     * @return A Socket connected to the given host and port.
     * @throws UnknownHostException  If the hostname cannot be resolved.
     * @throws IOException If an I/O error occurs while creating the Socket.
     */
    @Override
    public Socket createSocket(final String host, final int port,
                               final InetAddress localAddr, final int localPort)
    throws UnknownHostException, IOException
    {
        if (connProxy != null)
        {
            final Socket s = new Socket(connProxy);
            s.bind(new InetSocketAddress(localAddr, localPort));
            s.connect(new InetSocketAddress(host, port));
            return s;
        }
        return new Socket(host, port, localAddr, localPort);
    }

    /**
     * Creates a Socket connected to the given host and port and
     * originating from the specified local address and port.
     *
     * @param address The address of the host to connect to.
     * @param port The port to connect to.
     * @param localAddr  The local address to use.
     * @param localPort  The local port to use.
     * @return A Socket connected to the given host and port.
     * @throws IOException If an I/O error occurs while creating the Socket.
     */
    @Override
    public Socket createSocket(final InetAddress address, final int port,
                               final InetAddress localAddr, final int localPort)
    throws IOException
    {
        if (connProxy != null)
        {
            final Socket s = new Socket(connProxy);
            s.bind(new InetSocketAddress(localAddr, localPort));
            s.connect(new InetSocketAddress(address, port));
            return s;
        }
        return new Socket(address, port, localAddr, localPort);
    }

    /**
     * Creates a ServerSocket bound to a specified port.  A port
     * of 0 will create the ServerSocket on a system-determined free port.
     *
     * @param port  The port on which to listen, or 0 to use any free port.
     * @return A ServerSocket that will listen on a specified port.
     * @throws IOException If an I/O error occurs while creating
     *                        the ServerSocket.
     */
    public ServerSocket createServerSocket(final int port) throws IOException
    {
        return new ServerSocket(port);
    }

    /**
     * Creates a ServerSocket bound to a specified port with a given
     * maximum queue length for incoming connections.  A port of 0 will
     * create the ServerSocket on a system-determined free port.
     *
     * @param port  The port on which to listen, or 0 to use any free port.
     * @param backlog  The maximum length of the queue for incoming connections.
     * @return A ServerSocket that will listen on a specified port.
     * @throws IOException If an I/O error occurs while creating
     *                        the ServerSocket.
     */
    public ServerSocket createServerSocket(final int port, final int backlog)
    throws IOException
    {
        return new ServerSocket(port, backlog);
    }

    /**
     * Creates a ServerSocket bound to a specified port on a given local
     * address with a given maximum queue length for incoming connections.
     * A port of 0 will
     * create the ServerSocket on a system-determined free port.
     *
     * @param port  The port on which to listen, or 0 to use any free port.
     * @param backlog  The maximum length of the queue for incoming connections.
     * @param bindAddr  The local address to which the ServerSocket should bind.
     * @return A ServerSocket that will listen on a specified port.
     * @throws IOException If an I/O error occurs while creating
     *                        the ServerSocket.
     */
    public ServerSocket createServerSocket(final int port, final int backlog,
                                           final InetAddress bindAddr)
    throws IOException
    {
        return new ServerSocket(port, backlog, bindAddr);
    }
}

⏎ org/apache/commons/net/DefaultSocketFactory.java

Or download all of them as a single archive file:

File name: commons-net-3.8.0-sources.jar
File size: 437325 bytes
Release date: 2020-01-22
Download 

⇒ Download and Install commons-net.jar Binary Package

⇐ What Is commons-net.jar

⇑ Downloading and Reviewing commons-net.jar

⇑⇑ FAQ for Apache commons-net.jar