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/datatransfer/Transferable.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.datatransfer;

import java.io.IOException;

/**
 * Defines the interface for classes that can be used to provide data
 * for a transfer operation.
 * <p>
 * For information on using data transfer with Swing, see
 * <a href="https://docs.oracle.com/javase/tutorial/uiswing/dnd/index.html">
 * How to Use Drag and Drop and Data Transfer</a>,
 * a section in <em>The Java Tutorial</em>, for more information.
 *
 * @author      Amy Fowler
 */

public interface Transferable {

    /**
     * Returns an array of DataFlavor objects indicating the flavors the data
     * can be provided in.  The array should be ordered according to preference
     * for providing the data (from most richly descriptive to least descriptive).
     * @return an array of data flavors in which this data can be transferred
     */
    public DataFlavor[] getTransferDataFlavors();

    /**
     * Returns whether or not the specified data flavor is supported for
     * this object.
     * @param flavor the requested flavor for the data
     * @return boolean indicating whether or not the data flavor is supported
     */
    public boolean isDataFlavorSupported(DataFlavor flavor);

    /**
     * Returns an object which represents the data to be transferred.  The class
     * of the object returned is defined by the representation class of the flavor.
     *
     * @param flavor the requested flavor for the data
     * @see DataFlavor#getRepresentationClass
     * @exception IOException                if the data is no longer available
     *              in the requested flavor.
     * @exception UnsupportedFlavorException if the requested data flavor is
     *              not supported.
     */
    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException;

}

⏎ java/awt/datatransfer/Transferable.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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