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/protocol/giopmsgheaders/LocateRequestMessage_1_0.java

/*
 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package com.sun.corba.se.impl.protocol.giopmsgheaders;

import com.sun.corba.se.spi.ior.iiop.GIOPVersion;
import com.sun.corba.se.spi.orb.ORB;

import com.sun.corba.se.spi.ior.ObjectKey;

/**
 * This implements the GIOP 1.0 LocateRequest header.
 *
 * @author Ram Jeyaraman 05/14/2000
 */

public final class LocateRequestMessage_1_0 extends Message_1_0
        implements LocateRequestMessage {

    // Instance variables

    private ORB orb = null;
    private int request_id = (int) 0;
    private byte[] object_key = null;
    private ObjectKey objectKey = null;

    // Constructor

    LocateRequestMessage_1_0(ORB orb) {
        this.orb = orb;
    }

    LocateRequestMessage_1_0(ORB orb, int _request_id, byte[] _object_key) {
        super(Message.GIOPBigMagic, false, Message.GIOPLocateRequest, 0);
        this.orb = orb;
        request_id = _request_id;
        object_key = _object_key;
    }

    // Accessor methods (LocateRequestMessage interface)

    public int getRequestId() {
        return this.request_id;
    }

    public ObjectKey getObjectKey() {
        if (this.objectKey == null) {
            // this will raise a MARSHAL exception upon errors.
            this.objectKey = MessageBase.extractObjectKey(object_key, orb);
        }

        return this.objectKey;
    }

    // IO methods

    public void read(org.omg.CORBA.portable.InputStream istream) {
        super.read(istream);;
        this.request_id = istream.read_ulong();
        int _len0 = istream.read_long();
        this.object_key = new byte[_len0];
        istream.read_octet_array (this.object_key, 0, _len0);
    }

    public void write(org.omg.CORBA.portable.OutputStream ostream) {
        super.write(ostream);
        ostream.write_ulong(this.request_id);
        nullCheck(this.object_key);
        ostream.write_long(this.object_key.length);
        ostream.write_octet_array(this.object_key, 0, this.object_key.length);
    }

    public void callback(MessageHandler handler)
        throws java.io.IOException
    {
        handler.handleInput(this);
    }
} // class LocateRequestMessage_1_0

⏎ com/sun/corba/se/impl/protocol/giopmsgheaders/LocateRequestMessage_1_0.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 

⇒ Backup JDK 8 Installation Directory

⇐ JRE 8 rt.jar - org.* Package Source Code

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)