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/security/package-info.java

/*
 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/**
 * Provides the classes and interfaces for the security framework.
 * This includes classes that implement an easily configurable,
 * fine-grained access control security architecture.
 * This package also supports
 * the generation and storage of cryptographic public key pairs,
 * as well as a number of exportable cryptographic operations
 * including those for message digest and signature generation.  Finally,
 * this package provides classes that support signed/guarded objects
 * and secure random number generation.
 *
 * Many of the classes provided in this package (the cryptographic
 * and secure random number generator classes in particular) are
 * provider-based.  The class itself defines a programming interface
 * to which applications may write.  The implementations themselves may
 * then be written by independent third-party vendors and plugged
 * in seamlessly as needed.  Therefore application developers may
 * take advantage of any number of provider-based implementations
 * without having to add or rewrite code.
 *
 * <h2>Package Specification</h2>
 *
 * <ul>
 *   <li><a href="{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html">
 *     <b>Java&trade;
 *     Cryptography Architecture (JCA) Reference Guide</b></a></li>
 *
 *   <li>PKCS #8: Private-Key Information Syntax Standard, Version 1.2,
 *     November 1993</li>
 *
 *   <li><a href="{@docRoot}/../technotes/guides/security/StandardNames.html">
 *     <b>Java&trade;
 *     Cryptography Architecture Standard Algorithm Name
 *     Documentation</b></a></li>
 * </ul>
 *
 * <h2>Related Documentation</h2>
 *
 * For further documentation, please see:
 * <ul>
 *   <li><a href=
 *     "{@docRoot}/../technotes/guides/security/spec/security-spec.doc.html">
 *     <b>Java&trade;
 *     SE Platform Security Architecture</b></a></li>
 *
 *   <li><a href=
 *     "{@docRoot}/../technotes/guides/security/crypto/HowToImplAProvider.html">
 *     <b>How to Implement a Provider in the
 *     Java&trade; Cryptography Architecture
 *     </b></a></li>
 *
 *   <li><a href=
 *     "{@docRoot}/../technotes/guides/security/PolicyFiles.html"><b>
 *     Default Policy Implementation and Policy File Syntax
 *     </b></a></li>
 *
 *   <li><a href=
 *     "{@docRoot}/../technotes/guides/security/permissions.html"><b>
 *     Permissions in the
 *     Java&trade; SE Development Kit (JDK)
 *     </b></a></li>
 *
 *   <li><a href=
 *     "{@docRoot}/../technotes/guides/security/SecurityToolsSummary.html"><b>
 *     Summary of Tools for
 *     Java&trade; Platform Security
 *     </b></a></li>
 *
 *   <li><b>keytool</b>
 *     (<a href="{@docRoot}/../technotes/tools/unix/keytool.html">
 *       for Solaris/Linux</a>)
 *     (<a href="{@docRoot}/../technotes/tools/windows/keytool.html">
 *       for Windows</a>)
 *     </li>
 *
 *   <li><b>jarsigner</b>
 *     (<a href="{@docRoot}/../technotes/tools/unix/jarsigner.html">
 *       for Solaris/Linux</a>)
 *     (<a href="{@docRoot}/../technotes/tools/windows/jarsigner.html">
 *       for Windows</a>)
 *     </li>
 *
 * </ul>
 *
 * @since 1.1
 */
package java.security;

⏎ java/security/package-info.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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