JRE 8 rt.jar is the JAR file for JRE 8 RT (Runtime) libraries. JRE (Java Runtime) 8 is the runtime environment included in JDK 8. JRE 8 rt.jar libraries are divided into 6 packages:

com.* - Internal Oracle and Sun Microsystems libraries
java.* - Standard Java API libraries.
javax.* - Extended Java API libraries.
jdk.* -  JDK supporting libraries.
org.* - Third party libraries.
sun.* - Old libraries developed by Sun Microsystems.

JAR File Information:

Directory of C:\fyicenter\jdk-1.8.0_191\jre\lib
      63,596,151 rt.jar

Here is the list of Java classes of the com.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ com/sun/corba/se/impl/orbutil/HexOutputStream.java

/*
 * Copyright (c) 1996, 2002, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 *
 *
 *
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 *
 */

package com.sun.corba.se.impl.orbutil;

import java.io.StringWriter;
import java.io.OutputStream;
import java.io.IOException;

/**
 * Writes each input byte as a 2 byte hexidecimal output pair making it
 * possible to turn arbitrary binary data into an ASCII format.
 * The high 4 bits of the byte is translated into the first byte.
 *
 * @author      Jeff Nisewanger
 */
public class HexOutputStream extends OutputStream
{
    static private final char hex[] = {
        '0', '1', '2', '3', '4', '5', '6', '7',
        '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
    };

    private StringWriter writer;

    /**
     * Creates a new HexOutputStream.
     * @param w The underlying StringWriter.
     */
    public
        HexOutputStream(StringWriter w) {
        writer = w;
    }


    /**
     * Writes a byte. Will block until the byte is actually
     * written.
     * param b The byte to write out.
     * @exception java.io.IOException I/O error occurred.
     */
    public synchronized void write(int b) throws IOException {
        writer.write(hex[((b >> 4) & 0xF)]);
        writer.write(hex[((b >> 0) & 0xF)]);
    }

    public synchronized void write(byte[] b) throws IOException {
        write(b, 0, b.length);
    }

    public synchronized void write(byte[] b, int off, int len)
        throws IOException
    {
        for(int i=0; i < len; i++) {
            write(b[off + i]);
        }
    }
}

⏎ com/sun/corba/se/impl/orbutil/HexOutputStream.java

Or download all of them as a single archive file:

File name: jre-rt-com-1.8.0_191-src.zip
File size: 8099783 bytes
Release date: 2018-10-28
Download 

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