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/io/CRLFLineReader.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.io;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;

/**
 * CRLFLineReader implements a readLine() method that requires
 * exactly CRLF to terminate an input line.
 * This is required for IMAP, which allows bare CR and LF.
 *
 * @since 3.0
 */
public final class CRLFLineReader extends BufferedReader
{
    private static final char LF = '\n';
    private static final char CR = '\r';

    /**
     * Creates a CRLFLineReader that wraps an existing Reader
     * input source.
     * @param reader  The Reader input source.
     */
    public CRLFLineReader(final Reader reader)
    {
        super(reader);
    }

    /**
     * Read a line of text.
     * A line is considered to be terminated by carriage return followed immediately by a linefeed.
     * This contrasts with BufferedReader which also allows other combinations.
     * @since 3.0
     */
    @Override
    public String readLine() throws IOException {
        final StringBuilder sb = new StringBuilder();
        int intch;
        boolean prevWasCR = false;
        synchronized(lock) { // make thread-safe (hopefully!)
            while((intch = read()) != -1)
            {
                if (prevWasCR && intch == LF) {
                    return sb.substring(0, sb.length()-1);
                }
                if (intch == CR) {
                    prevWasCR = true;
                } else {
                    prevWasCR = false;
                }
                sb.append((char) intch);
            }
        }
        final String string = sb.toString();
        if (string.isEmpty()) { // immediate EOF
            return null;
        }
        return string;
    }
}

⏎ org/apache/commons/net/io/CRLFLineReader.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
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