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/resolver/Resolver.java

/*
 * Copyright (c) 2002, 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.resolver ;

/** Resolver defines the operations needed to support ORB operations for
 * resolve_initial_references and list_initial_services.
 */
public interface Resolver {
    /** Look up the name using this resolver and return the CORBA object
     * reference bound to this name, if any.  Returns null if no object
     * is bound to the name.
     */
    org.omg.CORBA.Object resolve( String name ) ;

    /** Return the entire collection of names that are currently bound
     * by this resolver.  Resulting collection contains only strings for
     * which resolve does not return null.  Some resolvers may not support
     * this method, in which case they return an empty set.
     */
    java.util.Set list() ;
}

⏎ com/sun/corba/se/spi/resolver/Resolver.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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