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/copyobject/FallbackObjectCopierImpl.java

/*
 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package com.sun.corba.se.impl.copyobject ;

import com.sun.corba.se.spi.copyobject.ObjectCopier ;
import com.sun.corba.se.spi.copyobject.ReflectiveCopyException ;

/** Trys a first ObjectCopier.  If the first throws a ReflectiveCopyException,
 * falls back and tries a second ObjectCopier.
 */
public class FallbackObjectCopierImpl implements ObjectCopier
{
    private ObjectCopier first ;
    private ObjectCopier second ;

    public FallbackObjectCopierImpl( ObjectCopier first,
        ObjectCopier second )
    {
        this.first = first ;
        this.second = second ;
    }

    public Object copy( Object src ) throws ReflectiveCopyException
    {
        try {
            return first.copy( src ) ;
        } catch (ReflectiveCopyException rce ) {
            // XXX log this fallback at a low level
            return second.copy( src ) ;
        }
    }
}

⏎ com/sun/corba/se/impl/copyobject/FallbackObjectCopierImpl.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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