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/swing/event/TreeSelectionListener.java

/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.swing.event;

import java.util.EventListener;

/**
 * The listener that's notified when the selection in a TreeSelectionModel
 * changes.
 * For more information and examples see
 * <a
 href="https://docs.oracle.com/javase/tutorial/uiswing/events/treeselectionlistener.html">How to Write a Tree Selection Listener</a>,
 * a section in <em>The Java Tutorial.</em>
 *
 * @see javax.swing.tree.TreeSelectionModel
 * @see javax.swing.JTree
 *
 * @author Scott Violet
 */
public interface TreeSelectionListener extends EventListener
{
    /**
      * Called whenever the value of the selection changes.
      * @param e the event that characterizes the change.
      */
    void valueChanged(TreeSelectionEvent e);
}

⏎ javax/swing/event/TreeSelectionListener.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

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