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/xerces/internal/jaxp/validation/AbstractXMLSchema.java

/*
 * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2005 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.
 */

package com.sun.org.apache.xerces.internal.jaxp.validation;

import java.util.HashMap;

import javax.xml.validation.Schema;
import javax.xml.validation.Validator;
import javax.xml.validation.ValidatorHandler;

/**
 * <p>Abstract implementation of Schema for W3C XML Schemas.</p>
 *
 * @author Michael Glavassevich, IBM
 * @version $Id: AbstractXMLSchema.java,v 1.6 2010-11-01 04:40:07 joehw Exp $
 */
abstract class AbstractXMLSchema extends Schema implements
        XSGrammarPoolContainer {

    /**
     * Map containing the initial values of features for
     * validators created using this grammar pool container.
     */
    private final HashMap fFeatures;

    /**
     * Map containing the initial values of properties for
     * validators created using this grammar pool container.
     */
    private final HashMap fProperties;

    public AbstractXMLSchema() {
        fFeatures = new HashMap();
        fProperties = new HashMap();
    }

    /*
     * Schema methods
     */

    /*
     * @see javax.xml.validation.Schema#newValidator()
     */
    public final Validator newValidator() {
        return new ValidatorImpl(this);
    }

    /*
     * @see javax.xml.validation.Schema#newValidatorHandler()
     */
    public final ValidatorHandler newValidatorHandler() {
        return new ValidatorHandlerImpl(this);
    }

    /*
     * XSGrammarPoolContainer methods
     */

    /**
     * Returns the initial value of a feature for validators created
     * using this grammar pool container or null if the validators
     * should use the default value.
     */
    public final Boolean getFeature(String featureId) {
        return (Boolean) fFeatures.get(featureId);
    }

    /*
     * Set a feature on the schema
     */
    public final void setFeature(String featureId, boolean state) {
        fFeatures.put(featureId, state ? Boolean.TRUE : Boolean.FALSE);
    }

    /**
     * Returns the initial value of a property for validators created
     * using this grammar pool container or null if the validators
     * should use the default value.
     */
    public final Object getProperty(String propertyId) {
        return fProperties.get(propertyId);
    }

    /*
     * Set a property on the schema
     */
    public final void setProperty(String propertyId, Object state) {
        fProperties.put(propertyId, state);
    }

} // AbstractXMLSchema

⏎ com/sun/org/apache/xerces/internal/jaxp/validation/AbstractXMLSchema.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 

⇒ Backup JDK 8 Installation Directory

⇐ JRE 8 rt.jar - org.* Package Source Code

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)