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/ior/OldObjectKeyTemplateBase.java

/*
 * Copyright (c) 2000, 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.ior;

import com.sun.corba.se.spi.ior.ObjectAdapterId ;

import org.omg.CORBA_2_3.portable.OutputStream ;

import com.sun.corba.se.spi.orb.ORB ;
import com.sun.corba.se.spi.orb.ORBVersion ;
import com.sun.corba.se.spi.orb.ORBVersionFactory ;

import com.sun.corba.se.impl.ior.ObjectKeyFactoryImpl ;

/**
 * @author Ken Cavanaugh
 */
public abstract class OldObjectKeyTemplateBase extends ObjectKeyTemplateBase
{
    public OldObjectKeyTemplateBase( ORB orb, int magic, int scid, int serverid,
        String orbid, ObjectAdapterId oaid )
    {
        super( orb, magic, scid, serverid, orbid, oaid ) ;

        // set version based on magic
        if (magic == ObjectKeyFactoryImpl.JAVAMAGIC_OLD)
            setORBVersion( ORBVersionFactory.getOLD() ) ;
        else if (magic == ObjectKeyFactoryImpl.JAVAMAGIC_NEW)
            setORBVersion( ORBVersionFactory.getNEW() ) ;
        else // any other magic should not be here
            throw wrapper.badMagic( new Integer( magic ) ) ;
    }
}

⏎ com/sun/corba/se/impl/ior/OldObjectKeyTemplateBase.java

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