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/event/ComponentListener.java

/*
 * Copyright (c) 1996, 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.event;

import java.util.EventListener;

/**
 * The listener interface for receiving component events.
 * The class that is interested in processing a component event
 * either implements this interface (and all the methods it
 * contains) or extends the abstract <code>ComponentAdapter</code> class
 * (overriding only the methods of interest).
 * The listener object created from that class is then registered with a
 * component using the component's <code>addComponentListener</code>
 * method. When the component's size, location, or visibility
 * changes, the relevant method in the listener object is invoked,
 * and the <code>ComponentEvent</code> is passed to it.
 * <P>
 * Component events are provided for notification purposes ONLY;
 * The AWT will automatically handle component moves and resizes
 * internally so that GUI layout works properly regardless of
 * whether a program registers a <code>ComponentListener</code> or not.
 *
 * @see ComponentAdapter
 * @see ComponentEvent
 * @see <a href="https://docs.oracle.com/javase/tutorial/uiswing/events/componentlistener.html">Tutorial: Writing a Component Listener</a>
 *
 * @author Carl Quinn
 * @since 1.1
 */
public interface ComponentListener extends EventListener {
    /**
     * Invoked when the component's size changes.
     */
    public void componentResized(ComponentEvent e);

    /**
     * Invoked when the component's position changes.
     */
    public void componentMoved(ComponentEvent e);

    /**
     * Invoked when the component has been made visible.
     */
    public void componentShown(ComponentEvent e);

    /**
     * Invoked when the component has been made invisible.
     */
    public void componentHidden(ComponentEvent e);
}

⏎ java/awt/event/ComponentListener.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 

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