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/corba/se/impl/util/PackagePrefixChecker.java

/*
 * Copyright (c) 1999, 2004, 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.corba.se.impl.util;

import java.io.File;

/**
 * PackagePrefixChecker provides static utility methods for getting package prefixes.
 * @author M. Mortazavi
 */

public final class PackagePrefixChecker {


    private static final String PACKAGE_PREFIX = "org.omg.stub.";

    public static String packagePrefix(){ return PACKAGE_PREFIX;}

    public static String correctPackageName (String p){
        if (p==null) return p;
        if ( hasOffendingPrefix(p))
            {
               return PACKAGE_PREFIX+p;
            }
        return p;
    }

    public static boolean isOffendingPackage(String p){
        return
            !(p==null)
            &&
            ( false || hasOffendingPrefix(p) );
    }

    public static boolean hasOffendingPrefix(String p){
        return
            (      p.startsWith("java.") || p.equals("java")
                // || p.startsWith("com.sun.") || p.equals("com.sun")
                || p.startsWith("net.jini.") || p.equals("net.jini")
                || p.startsWith("jini.") || p.equals("jini")
                || p.startsWith("javax.") || p.equals("javax")
            );
    }

    public static boolean hasBeenPrefixed(String p){
        return p.startsWith(packagePrefix());
    }

    public static String withoutPackagePrefix(String p){
        if(hasBeenPrefixed(p)) return p.substring(packagePrefix().length());
        else return p;
    }

}

⏎ com/sun/corba/se/impl/util/PackagePrefixChecker.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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