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/monitoring/LongMonitoredAttributeBase.java

/*
 * Copyright (c) 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.monitoring;

import java.util.*;

/**
 * <p>
 *
 * @author Hemanth Puttaswamy
 * </p>
 * <p>
 * A Cleaner Abstraction to provide a Monitored Attribute of type 'Long'
 * </p>
 */
public abstract class LongMonitoredAttributeBase extends MonitoredAttributeBase {

  ///////////////////////////////////////
  // operations


/**
 * <p>
 * Constructs LongMonitoredAttribute, by creating the
 * MonitoredAttributeInfo with 'Long' as the class type.
 * Users are expected to extend this class and provide the implementation
 * for getValue() and if needed clearState() as well.
 * </p>
 * <p>
 *
 * @param name of tthe MonitoredAttribute
 * </p>
 * <p>
 * @param description of the Attribute, Please provid a well thought out
 * description, so that the admin can make sense of the attribute supplied.
 * </p>
 */
    public  LongMonitoredAttributeBase(String name, String description) {
        super( name );
        MonitoredAttributeInfoFactory f =
            MonitoringFactories.getMonitoredAttributeInfoFactory();
        MonitoredAttributeInfo maInfo = f.createMonitoredAttributeInfo(
                description, Long.class, false, false );
        this.setMonitoredAttributeInfo( maInfo );
    } // end LongMonitoredAttributeBase


} // end LongMonitoredAttributeBase

⏎ com/sun/corba/se/spi/monitoring/LongMonitoredAttributeBase.java

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