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

⏎ org/w3c/dom/DOMImplementationSource.java

/*
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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/*
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 * Copyright (c) 2004 World Wide Web Consortium,
 *
 * (Massachusetts Institute of Technology, European Research Consortium for
 * Informatics and Mathematics, Keio University). All Rights Reserved. This
 * work is distributed under the W3C(r) Software License [1] in the hope that
 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
 */

package org.w3c.dom;

/**
 * This interface permits a DOM implementer to supply one or more
 * implementations, based upon requested features and versions, as specified
 * in <a href='http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/core.html#DOMFeatures'>DOM
 * Features</a>. Each implemented <code>DOMImplementationSource</code> object is
 * listed in the binding-specific list of available sources so that its
 * <code>DOMImplementation</code> objects are made available.
 * <p>See also the <a href='http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407'>Document Object Model (DOM) Level 3 Core Specification</a>.
 * @since DOM Level 3
 */
public interface DOMImplementationSource {
    /**
     *  A method to request the first DOM implementation that supports the
     * specified features.
     * @param features  A string that specifies which features and versions
     *   are required. This is a space separated list in which each feature
     *   is specified by its name optionally followed by a space and a
     *   version number.  This method returns the first item of the list
     *   returned by <code>getDOMImplementationList</code>.  As an example,
     *   the string <code>"XML 3.0 Traversal +Events 2.0"</code> will
     *   request a DOM implementation that supports the module "XML" for its
     *   3.0 version, a module that support of the "Traversal" module for
     *   any version, and the module "Events" for its 2.0 version. The
     *   module "Events" must be accessible using the method
     *   <code>Node.getFeature()</code> and
     *   <code>DOMImplementation.getFeature()</code>.
     * @return The first DOM implementation that support the desired
     *   features, or <code>null</code> if this source has none.
     */
    public DOMImplementation getDOMImplementation(String features);

    /**
     * A method to request a list of DOM implementations that support the
     * specified features and versions, as specified in .
     * @param features A string that specifies which features and versions
     *   are required. This is a space separated list in which each feature
     *   is specified by its name optionally followed by a space and a
     *   version number. This is something like: "XML 3.0 Traversal +Events
     *   2.0"
     * @return A list of DOM implementations that support the desired
     *   features.
     */
    public DOMImplementationList getDOMImplementationList(String features);

}

⏎ org/w3c/dom/DOMImplementationSource.java

Or download all of them as a single archive file:

File name: jre-rt-org-1.8.0_191-src.zip
File size: 951125 bytes
Release date: 2018-10-28
Download 

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

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

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