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/management/remote/JMXAuthenticator.java

/*
 * Copyright (c) 2003, 2007, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.management.remote;

import java.security.Principal;
import javax.security.auth.Subject;

/**
 * <p>Interface to define how remote credentials are converted into a
 * JAAS Subject.  This interface is used by the RMI Connector Server,
 * and can be used by other connector servers.</p>
 *
 * <p>The user-defined authenticator instance is passed to the
 * connector server in the environment map as the value of the
 * attribute {@link JMXConnectorServer#AUTHENTICATOR}.  For connector
 * servers that use only this authentication system, if this attribute
 * is not present or its value is <code>null</code> then no user
 * authentication will be performed and full access to the methods
 * exported by the <code>MBeanServerConnection</code> object will be
 * allowed.</p>
 *
 * <p>If authentication is successful then an authenticated
 * {@link Subject subject} filled in with its associated
 * {@link Principal principals} is returned. Authorization checks
 * will be then performed based on the given set of principals.</p>
 *
 * @since 1.5
 */
public interface JMXAuthenticator {

    /**
     * <p>Authenticates the <code>MBeanServerConnection</code> client
     * with the given client credentials.</p>
     *
     * @param credentials the user-defined credentials to be passed
     * into the server in order to authenticate the user before
     * creating the <code>MBeanServerConnection</code>.  The actual
     * type of this parameter, and whether it can be null, depends on
     * the connector.
     *
     * @return the authenticated subject containing its associated principals.
     *
     * @exception SecurityException if the server cannot authenticate the user
     * with the provided credentials.
     */
    public Subject authenticate(Object credentials);
}

⏎ javax/management/remote/JMXAuthenticator.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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