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/w3c/dom/events/UIEvent.java

/*
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

/*
 *
 *
 *
 *
 *
 * Copyright (c) 2000 World Wide Web Consortium,
 * (Massachusetts Institute of Technology, Institut National de
 * Recherche en Informatique et en Automatique, Keio University). All
 * Rights Reserved. This program is distributed under the W3C's Software
 * Intellectual Property License. This program is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.
 * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
 */

package org.w3c.dom.events;

import org.w3c.dom.views.AbstractView;

/**
 * The <code>UIEvent</code> interface provides specific contextual information
 * associated with User Interface events.
 * <p>See also the <a href='http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113'>Document Object Model (DOM) Level 2 Events Specification</a>.
 * @since DOM Level 2
 */
public interface UIEvent extends Event {
    /**
     * The <code>view</code> attribute identifies the <code>AbstractView</code>
     *  from which the event was generated.
     */
    public AbstractView getView();

    /**
     * Specifies some detail information about the <code>Event</code>,
     * depending on the type of event.
     */
    public int getDetail();

    /**
     * The <code>initUIEvent</code> method is used to initialize the value of
     * a <code>UIEvent</code> created through the <code>DocumentEvent</code>
     * interface. This method may only be called before the
     * <code>UIEvent</code> has been dispatched via the
     * <code>dispatchEvent</code> method, though it may be called multiple
     * times during that phase if necessary. If called multiple times, the
     * final invocation takes precedence.
     * @param typeArg Specifies the event type.
     * @param canBubbleArg Specifies whether or not the event can bubble.
     * @param cancelableArg Specifies whether or not the event's default
     *   action can be prevented.
     * @param viewArg Specifies the <code>Event</code>'s
     *   <code>AbstractView</code>.
     * @param detailArg Specifies the <code>Event</code>'s detail.
     */
    public void initUIEvent(String typeArg,
                            boolean canBubbleArg,
                            boolean cancelableArg,
                            AbstractView viewArg,
                            int detailArg);

}

⏎ org/w3c/dom/events/UIEvent.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)