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/Accessible.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.accessibility;

/**
 * Interface Accessible is the main interface for the accessibility package.
 * All components that support
 * the accessibility package must implement this interface.
 * It contains a single method, {@link #getAccessibleContext}, which
 * returns an instance of the class {@link AccessibleContext}.
 *
 * @author      Peter Korn
 * @author      Hans Muller
 * @author      Willie Walker
 */
public interface Accessible {

    /**
     * Returns the AccessibleContext associated with this object.  In most
     * cases, the return value should not be null if the object implements
     * interface Accessible.  If a component developer creates a subclass
     * of an object that implements Accessible, and that subclass
     * is not Accessible, the developer should override the
     * getAccessibleContext method to return null.
     * @return the AccessibleContext associated with this object
     */
    public AccessibleContext getAccessibleContext();
}

⏎ javax/accessibility/Accessible.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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