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/org/apache/xalan/internal/xsltc/dom/CollatorFactoryBase.java

/*
 * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: CollatorFactoryBase.java,v 1.2.4.1 2005/09/06 06:03:08 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.dom;

import java.text.Collator;
import java.util.Locale;

import com.sun.org.apache.xalan.internal.xsltc.CollatorFactory;

/**
 * @author W. Eliot Kimber (eliot@isogen.com)
 */
public class CollatorFactoryBase implements CollatorFactory {

    public static final Locale DEFAULT_LOCALE = Locale.getDefault();
    public static final Collator DEFAULT_COLLATOR = Collator.getInstance();

    public CollatorFactoryBase() {
    }

    public Collator getCollator(String lang, String country) {
        return Collator.getInstance(new Locale(lang, country));
    }

    public Collator getCollator(Locale locale) {
        if (locale == DEFAULT_LOCALE)
            return DEFAULT_COLLATOR;
        else
            return Collator.getInstance(locale);
    }
}

⏎ com/sun/org/apache/xalan/internal/xsltc/dom/CollatorFactoryBase.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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