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

⏎ com/sun/org/apache/xalan/internal/Version.java

/*
 * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2003-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: Version.java,v 1.1.2.1 2005/08/01 02:11:19 jeffsuttor Exp $
 */
package com.sun.org.apache.xalan.internal;

/**
 * Administrative class to keep track of the version number of
 * the Xalan release.
 * <P>This class implements the upcoming standard of having
 * org.apache.project-name.Version.getVersion() be a standard way
 * to get version information.  This class will replace the older
 * com.sun.org.apache.xalan.internal.processor.Version class.</P>
 * <P>See also: com/sun/org/apache/xalan/internal/res/XSLTInfo.properties for
 * information about the version of the XSLT spec we support.</P>
 * @xsl.usage general
 */
public class Version
{

  /**
   * Get the basic version string for the current Xalan release.
   * Version String formatted like
   * <CODE>"<B>Xalan</B> <B>Java</B> v.r[.dd| <B>D</B>nn]"</CODE>.
   *
   * Futurework: have this read version info from jar manifest.
   *
   * @return String denoting our current version
   */
  public static String getVersion()
  {
     return getProduct()+" "+getImplementationLanguage()+" "
           +getMajorVersionNum()+"."+getReleaseVersionNum()+"."
           +( (getDevelopmentVersionNum() > 0) ?
               ("D"+getDevelopmentVersionNum()) : (""+getMaintenanceVersionNum()));
  }

  /**
   * Print the processor version to the command line.
   *
   * @param argv command line arguments, unused.
   */
  public static void _main(String argv[])
  {
    System.out.println(getVersion());
  }

  /**
   * Name of product: Xalan.
   */
  public static String getProduct()
  {
    return "Xalan";
  }

  /**
   * Implementation Language: Java.
   */
  public static String getImplementationLanguage()
  {
    return "Java";
  }


  /**
   * Major version number.
   * Version number. This changes only when there is a
   *          significant, externally apparent enhancement from
   *          the previous release. 'n' represents the n'th
   *          version.
   *
   *          Clients should carefully consider the implications
   *          of new versions as external interfaces and behaviour
   *          may have changed.
   */
  public static int getMajorVersionNum()
  {
    return 2;

  }

  /**
   * Release Number.
   * Release number. This changes when:
   *            -  a new set of functionality is to be added, eg,
   *               implementation of a new W3C specification.
   *            -  API or behaviour change.
   *            -  its designated as a reference release.
   */
  public static int getReleaseVersionNum()
  {
    return 7;
  }

  /**
   * Maintenance Drop Number.
   * Optional identifier used to designate maintenance
   *          drop applied to a specific release and contains
   *          fixes for defects reported. It maintains compatibility
   *          with the release and contains no API changes.
   *          When missing, it designates the final and complete
   *          development drop for a release.
   */
  public static int getMaintenanceVersionNum()
  {
    return 0;
  }

  /**
   * Development Drop Number.
   * Optional identifier designates development drop of
   *          a specific release. D01 is the first development drop
   *          of a new release.
   *
   *          Development drops are works in progress towards a
   *          compeleted, final release. A specific development drop
   *          may not completely implement all aspects of a new
   *          feature, which may take several development drops to
   *          complete. At the point of the final drop for the
   *          release, the D suffix will be omitted.
   *
   *          Each 'D' drops can contain functional enhancements as
   *          well as defect fixes. 'D' drops may not be as stable as
   *          the final releases.
   */
  public static int getDevelopmentVersionNum()
  {
    try {
        if ((new String("")).length() == 0)
          return 0;
        else
          return Integer.parseInt("");
    } catch (NumberFormatException nfe) {
           return 0;
    }
  }
}

⏎ com/sun/org/apache/xalan/internal/Version.java

Or download all of them as a single archive file:

File name: jre-rt-com-1.8.0_191-src.zip
File size: 8099783 bytes
Release date: 2018-10-28
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