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/rmi/registry/RegistryHandler.java

/*
 * Copyright (c) 1997, 2004, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.rmi.registry;

import java.rmi.RemoteException;
import java.rmi.UnknownHostException;

/**
 * <code>RegistryHandler</code> is an interface used internally by the RMI
 * runtime in previous implementation versions.  It should never be accessed
 * by application code.
 *
 * @author  Ann Wollrath
 * @since   JDK1.1
 * @deprecated no replacement
 */
@Deprecated
public interface RegistryHandler {

    /**
     * Returns a "stub" for contacting a remote registry
     * on the specified host and port.
     *
     * @deprecated no replacement.  As of the Java 2 platform v1.2, RMI no
     * longer uses the <code>RegistryHandler</code> to obtain the registry's
     * stub.
     * @param host name of remote registry host
     * @param port remote registry port
     * @return remote registry stub
     * @throws RemoteException if a remote error occurs
     * @throws UnknownHostException if unable to resolve given hostname
     */
    @Deprecated
    Registry registryStub(String host, int port)
        throws RemoteException, UnknownHostException;

    /**
     * Constructs and exports a Registry on the specified port.
     * The port must be non-zero.
     *
     * @deprecated no replacement.  As of the Java 2 platform v1.2, RMI no
     * longer uses the <code>RegistryHandler</code> to obtain the registry's
     * implementation.
     * @param port port to export registry on
     * @return registry stub
     * @throws RemoteException if a remote error occurs
     */
    @Deprecated
    Registry registryImpl(int port) throws RemoteException;
}

⏎ java/rmi/registry/RegistryHandler.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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