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/javadoc/Tag.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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 *
 *
 *
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 *
 */

package com.sun.javadoc;

import java.text.BreakIterator;
import java.util.Locale;

/**
 * Represents a simple documentation tag, such as @since, @author, @version.
 * Given a tag (e.g. "@since 1.2"), holds tag name (e.g. "@since")
 * and tag text (e.g. "1.2").  Tags with structure or which require
 * special processing are handled by subclasses such as ParamTag
 * (for @param), SeeTag (for @see and {@link}), and ThrowsTag
 * (for @throws).
 *
 * @author Robert Field
 * @author Atul M Dambalkar
 * @see SeeTag
 * @see ParamTag
 * @see ThrowsTag
 * @see SerialFieldTag
 * @see Doc#tags()
 *
 */
public interface Tag {

    /**
     * Return the name of this tag.  The name is the string
     * starting with "@" that is used in a doc comment, such as
     * <code>@return</code>.  For inline tags, such as
     * <code>{&#064;link}</code>, the curly brackets
     * are not part of the name, so in this example the name
     * would be simply <code>@link</code>.
     *
     * @return the name of this tag
     */
    String name();

    /**
     * Return the containing {@link Doc} of this Tag element.
     *
     * @return the containing {@link Doc} of this Tag element
     */
    Doc holder();

    /**
     * Return the kind of this tag.
     * For most tags,
     * <code>kind()&nbsp;==&nbsp;name()</code>;
     * the following table lists those cases where there is more
     * than one tag of a given kind:
     *
     * <table border="1" cellpadding="4" cellspacing="0" summary="related tags">
     * <tr><th>{@code kind()  }</th>  <th>{@code name()      }</th></tr>
     * <tr><td>{@code @throws }</td>  <td>{@code @throws     }</td></tr>
     * <tr><td>{@code @throws }</td>  <td>{@code @exception  }</td></tr>
     * <tr><td>{@code @see    }</td>  <td>{@code @see        }</td></tr>
     * <tr><td>{@code @see    }</td>  <td>{@code @link       }</td></tr>
     * <tr><td>{@code @see    }</td>  <td>{@code @linkplain  }</td></tr>
     * <tr><td>{@code @serial }</td>  <td>{@code @serial     }</td></tr>
     * <tr><td>{@code @serial }</td>  <td>{@code @serialData }</td></tr>
     * </table>
     *
     * @return the kind of this tag.
     */
    String kind();

    /**
     * Return the text of this tag, that is, the portion beyond tag name.
     *
     * @return the text of this tag
     */
    String text();

    /**
     * Convert this object to a string.
     */
    String toString();

    /**
     * For a documentation comment with embedded <code>{&#064;link}</code>
     * tags, return an array of <code>Tag</code> objects.  The entire
     * doc comment is broken down into strings separated by
     * <code>{&#064;link}</code> tags, where each successive element
     * of the array represents either a string or
     * <code>{&#064;link}</code> tag, in order, from start to end.
     * Each string is represented by a <code>Tag</code> object of
     * name "Text", where {@link #text()} returns the string.  Each
     * <code>{&#064;link}</code> tag is represented by a
     * {@link SeeTag} of name "@link" and kind "@see".
     * For example, given the following comment
     * tag:
     * <p>
     *  <code>This is a {&#064;link Doc commentlabel} example.</code>
     * <p>
     * return an array of Tag objects:
     * <ul>
     *    <li> tags[0] is a {@link Tag} with name "Text" and text consisting
     *         of "This is a "
     *    <li> tags[1] is a {@link SeeTag} with name "@link", referenced
     *         class <code>Doc</code> and label "commentlabel"
     *    <li> tags[2] is a {@link Tag} with name "Text" and text consisting
     *         of " example."
     * </ul>
     *
     * @return Tag[] array of tags
     * @see ParamTag
     * @see ThrowsTag
     */
    Tag[] inlineTags();

    /**
     * Return the first sentence of the comment as an array of tags.
     * Includes inline tags
     * (i.e. {&#64;link <i>reference</i>} tags)  but not
     * block tags.
     * Each section of plain text is represented as a {@link Tag}
     * of kind "Text".
     * Inline tags are represented as a {@link SeeTag} of kind "@link".
     * If the locale is English language, the first sentence is
     * determined by the rules described in the Java Language
     * Specification (first version): &quot;This sentence ends
     * at the first period that is followed by a blank, tab, or
     * line terminator or at the first tagline.&quot;, in
     * addition a line will be terminated by paragraph and
     * section terminating HTML tags: &lt;p&gt;  &lt;/p&gt;  &lt;h1&gt;
     * &lt;h2&gt;  &lt;h3&gt; &lt;h4&gt;  &lt;h5&gt;  &lt;h6&gt;
     * &lt;hr&gt;  &lt;pre&gt;  or &lt;/pre&gt;.
     * If the locale is not English, the sentence end will be
     * determined by
     * {@link BreakIterator#getSentenceInstance(Locale)}.
     *
     * @return an array of {@link Tag} objects representing the
     *         first sentence of the comment
     */
    Tag[] firstSentenceTags();

    /**
     * Return the source position of this tag.
     * @return the source position of this tag.
     */
    public SourcePosition position();
}

⏎ com/sun/javadoc/Tag.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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