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/SeeTag.java

/*
 * Copyright (c) 1998, 2002, 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;

/**
 * Represents a user-defined cross-reference to related documentation.
 * The tag can reference a package, class or member, or can hold
 * plain text.  (The plain text might be a reference
 * to something not online, such as a printed book, or be a hard-coded
 * HTML link.)  The reference can either be inline with the comment,
 * using <code>&#123;@link}</code>, or a separate block comment,
 * using <code>@see</code>.
 * Method <code>name()</code> returns "@link" (no curly braces) or
 * "@see", depending on the tag.
 * Method <code>kind()</code> returns "@see" for both tags.
 *
 * @author Kaiyang Liu (original)
 * @author Robert Field (rewrite)
 * @author Atul M Dambalkar
 *
 */
public interface SeeTag extends Tag {

    /**
     * Get the label of the <code>@see</code> tag.
     * Return null if no label is present.
     * For example, for:
     * <p>
     *    &nbsp;&nbsp;<code>@see String#trim() the trim method</code>
     * </p>
     * return "the trim method".
     */
    String label();

    /**
     * Get the package doc when <code>@see</code> references only a package.
     * Return null if the package cannot be found, or if
     * <code>@see</code> references any other element (class,
     * interface, field, constructor, method) or non-element.
     * For example, for:
     * <p>
     *   &nbsp;&nbsp;<code>@see java.lang</code>
     * </p>
     * return the <code>PackageDoc</code> for <code>java.lang</code>.
     */
    public PackageDoc referencedPackage();

    /**
     * Get the class or interface name of the <code>@see</code> reference.
     * The name is fully qualified if the name specified in the
     * original <code>@see</code> tag was fully qualified, or if the class
     * or interface can be found; otherwise it is unqualified.
     * If <code>@see</code> references only a package name, then return
     * the package name instead.
     * For example, for:
     * <p>
     *   &nbsp;&nbsp;<code>@see String#valueOf(java.lang.Object)</code>
     * </p>
     * return "java.lang.String".
     * For "<code>@see java.lang</code>", return "java.lang".
     * Return null if <code>@see</code> references a non-element, such as
     * <code>@see &lt;a href="java.sun.com"&gt;</code>.
     */
    String referencedClassName();

    /**
     * Get the class doc referenced by the class name part of @see.
     * Return null if the class cannot be found.
     * For example, for:
     * <p>
     *   &nbsp;&nbsp;<code>@see String#valueOf(java.lang.Object)</code>
     * </p>
     * return the <code>ClassDoc</code> for <code>java.lang.String</code>.
     */
    ClassDoc referencedClass();

    /**
     * Get the field, constructor or method substring of the <code>@see</code>
     * reference. Return null if the reference is to any other
     * element or to any non-element.
     * References to member classes (nested classes) return null.
     * For example, for:
     * <p>
     *   &nbsp;&nbsp;<code>@see String#startsWith(String)</code>
     * </p>
     * return "startsWith(String)".
     */
    String referencedMemberName();

    /**
     * Get the member doc for the field, constructor or method
     * referenced by <code>@see</code>. Return null if the member cannot
     * be found or if the reference is to any other element or to any
     * non-element.
     * References to member classes (nested classes) return null.
     * For example, for:
     * <p>
     *   &nbsp;&nbsp;<code>@see String#startsWith(java.lang.String)</code>
     * </p>
     * return the <code>MethodDoc</code> for <code>startsWith</code>.
     */
    MemberDoc referencedMember();
}

⏎ com/sun/javadoc/SeeTag.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
Download 

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