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/portable/ResponseHandler.java

/*
 * Copyright (c) 1998, 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package org.omg.CORBA.portable;

/**
This interface is supplied by an ORB to a servant at invocation time and allows
the servant to later retrieve an OutputStream for returning the invocation results.
*/

public interface ResponseHandler {
    /**
     * Called by the servant during a method invocation. The servant
     * should call this method to create a reply marshal buffer if no
     * exception occurred.
     *
     * @return an OutputStream suitable for marshalling the reply.
     *
     * @see <a href="package-summary.html#unimpl"><code>portable</code>
     * package comments for unimplemented features</a>
     */
    OutputStream createReply();

    /**
     * Called by the servant during a method invocation. The servant
     * should call this method to create a reply marshal buffer if a
     * user exception occurred.
     *
     * @return an OutputStream suitable for marshalling the exception
     * ID and the user exception body.
     */
    OutputStream createExceptionReply();
}

⏎ org/omg/CORBA/portable/ResponseHandler.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)