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

⏎ java/awt/EventFilter.java

/*
 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.awt;

interface EventFilter {

    /**
     * Enumeration for possible values for <code>acceptEvent(AWTEvent ev)</code> method.
     * @see EventDispatchThread#pumpEventsForFilter
     */
    static enum FilterAction {
        /**
         * ACCEPT means that this filter do not filter the event and allowes other
         * active filters to proceed it. If all the active filters accept the event, it
         * is dispatched by the <code>EventDispatchThread</code>
         * @see EventDispatchThread#pumpEventsForFilter
         */
        ACCEPT,
        /**
         * REJECT means that this filter filter the event. No other filters are queried,
         * and the event is not dispatched by the <code>EventDispatchedThread</code>
         * @see EventDispatchThread#pumpEventsForFilter
         */
        REJECT,
        /**
         * ACCEPT_IMMEDIATELY means that this filter do not filter the event, no other
         * filters are queried and to proceed it, and it is dispatched by the
         * <code>EventDispatchThread</code>
         * It is not recommended to use ACCEPT_IMMEDIATELY as there may be some active
         * filters not queried yet that do not accept this event. It is primarily used
         * by modal filters.
         * @see EventDispatchThread#pumpEventsForFilter
         * @see ModalEventFilter
         */
        ACCEPT_IMMEDIATELY
    };

    FilterAction acceptEvent(AWTEvent ev);
}

⏎ java/awt/EventFilter.java

Or download all of them as a single archive file:

File name: jre-rt-java-1.8.0_191-src.zip
File size: 6664831 bytes
Release date: 2018-10-28
Download 

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

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