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/accessibility/AccessibleExtendedComponent.java

/*
 * Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.accessibility;

/**
 * The AccessibleExtendedComponent interface should be supported by any object
 * that is rendered on the screen.  This interface provides the standard
 * mechanism for an assistive technology to determine the extended
 * graphical representation of an object.  Applications can determine
 * if an object supports the AccessibleExtendedComponent interface by first
 * obtaining its AccessibleContext
 * and then calling the
 * {@link AccessibleContext#getAccessibleComponent} method.
 * If the return value is not null and the type of the return value is
 * AccessibleExtendedComponent, the object supports this interface.
 *
 * @see Accessible
 * @see Accessible#getAccessibleContext
 * @see AccessibleContext
 * @see AccessibleContext#getAccessibleComponent
 *
 * @author      Lynn Monsanto
 * @since 1.4
 */
public interface AccessibleExtendedComponent extends AccessibleComponent {

    /**
     * Returns the tool tip text
     *
     * @return the tool tip text, if supported, of the object;
     * otherwise, null
     */
    public String getToolTipText();

    /**
     * Returns the titled border text
     *
     * @return the titled border text, if supported, of the object;
     * otherwise, null
     */
    public String getTitledBorderText();

    /**
     * Returns key bindings associated with this object
     *
     * @return the key bindings, if supported, of the object;
     * otherwise, null
     * @see AccessibleKeyBinding
     */
    public AccessibleKeyBinding getAccessibleKeyBinding();
}

⏎ javax/accessibility/AccessibleExtendedComponent.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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