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 org.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ org/omg/CORBA_2_3/portable/ObjectImpl.java

/*
 * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
/*
 * Licensed Materials - Property of IBM
 * RMI-IIOP v1.0
 * Copyright IBM Corp. 1998 1999  All Rights Reserved
 *
 */

package org.omg.CORBA_2_3.portable;

import org.omg.CORBA_2_3.portable.Delegate;

/**
 * ObjectImpl class is the base class for all stubs.  It provides the
 * basic delegation mechanism.  It extends org.omg.CORBA.portable.ObjectImpl
 * and provides new methods defined by CORBA 2.3.
 *
 * @see org.omg.CORBA.portable.ObjectImpl
 * @author  OMG
 * @since   JDK1.2
 */


public abstract class ObjectImpl extends org.omg.CORBA.portable.ObjectImpl {

    /** Returns the codebase for this object reference.
     * @return the codebase as a space delimited list of url strings or
     * null if none.
     */
    public java.lang.String _get_codebase() {
        org.omg.CORBA.portable.Delegate delegate = _get_delegate();
        if (delegate instanceof Delegate)
            return ((Delegate) delegate).get_codebase(this);
        return null;
    }
}

⏎ org/omg/CORBA_2_3/portable/ObjectImpl.java

Or download all of them as a single archive file:

File name: jre-rt-org-1.8.0_191-src.zip
File size: 951125 bytes
Release date: 2018-10-28
Download 

⇒ JRE 8 rt.jar - com.* Package Source Code

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

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)