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/spi/ior/ObjectKey.java

/*
 * Copyright (c) 2002, 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.spi.ior;

import com.sun.corba.se.spi.protocol.CorbaServerRequestDispatcher ;

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

/** The full object key, which is contained in an IIOPProfile.
* The object identifier corresponds to the information passed into
* POA::create_reference_with_id and POA::create_reference
* (in the POA case).  The template
* represents the information that is object adapter specific and
* shared across multiple ObjectKey instances.
*/
public interface ObjectKey extends Writeable
{
    /** Return the object identifier for this Object key.
    */
    ObjectId getId() ;

    /** Return the template for this object key.
    */
    ObjectKeyTemplate getTemplate()  ;

    byte[] getBytes( org.omg.CORBA.ORB orb ) ;

    CorbaServerRequestDispatcher getServerRequestDispatcher( ORB orb ) ;
}

⏎ com/sun/corba/se/spi/ior/ObjectKey.java

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