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

⏎ javax/naming/event/NamingExceptionEvent.java

/*
 * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package javax.naming.event;

import javax.naming.NamingException;

/**
  * This class represents an event fired when the procedures/processes
  * used to collect information for notifying listeners of
  * <tt>NamingEvent</tt>s threw a <tt>NamingException</tt>.
  * This can happen, for example, if the server which the listener is using
  * aborts subsequent to the <tt>addNamingListener()</tt> call.
  *
  * @author Rosanna Lee
  * @author Scott Seligman
  *
  * @see NamingListener#namingExceptionThrown
  * @see EventContext
  * @since 1.3
  */

public class NamingExceptionEvent extends java.util.EventObject {
    /**
     * Contains the exception that was thrown
     * @serial
     */
    private NamingException exception;

    /**
     * Constructs an instance of <tt>NamingExceptionEvent</tt> using
     * the context in which the <tt>NamingException</tt> was thrown and the exception
     * that was thrown.
     *
     * @param source The non-null context in which the exception was thrown.
     * @param exc    The non-null <tt>NamingException</tt> that was thrown.
     *
     */
    public NamingExceptionEvent(EventContext source, NamingException exc) {
        super(source);
        exception = exc;
    }

    /**
     * Retrieves the exception that was thrown.
     * @return The exception that was thrown.
     */
    public NamingException getException() {
        return exception;
    }

    /**
     * Retrieves the <tt>EventContext</tt> that fired this event.
     * This returns the same object as <tt>EventObject.getSource()</tt>.
     * @return The non-null <tt>EventContext</tt> that fired this event.
     */
    public EventContext getEventContext() {
        return (EventContext)getSource();
    }

    /**
     * Invokes the <tt>namingExceptionThrown()</tt> method on
     * a listener using this event.
     * @param listener The non-null naming listener on which to invoke
     * the method.
     */
    public void dispatch(NamingListener listener) {
        listener.namingExceptionThrown(this);
    }

    private static final long serialVersionUID = -4877678086134736336L;
}

⏎ javax/naming/event/NamingExceptionEvent.java

Or download all of them as a single archive file:

File name: jre-rt-javax-1.8.0_191-src.zip
File size: 5381005 bytes
Release date: 2018-10-28
Download 

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

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

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)