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/MonitoredAttribute.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 com.sun.corba.se.spi.monitoring.MonitoredAttributeInfo;
import java.util.*;

/**
 * <p>
 *
 * @author Hemanth Puttaswamy
 * </p>
 * <p>
 * Monitored Attribute is the interface to represent a Monitorable
 * Attribute. Using this interface, one can get the value of the attribute
 * and set the value if it is a writeable attribute.
 * </p>
 */
public interface MonitoredAttribute {

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

/**
 * <p>
 * Gets the Monitored Attribute Info for the attribute.
 * </p>
 * <p>
 *
 * @param monitoredAttributeInfo for this Monitored Attribute.
 * </p>
 */
    public MonitoredAttributeInfo getAttributeInfo();
/**
 * <p>
 * Sets the value for the Monitored Attribute if isWritable() is false, the
 * method will throw ILLEGAL Operation exception.
 *
 * Also, the type of 'value' should be same as specified in the
 * MonitoredAttributeInfo for a particular instance.
 * </p>
 * <p>
 *
 * @param value should be any one of the Basic Java Type Objects which are
 * Long, Double, Float, String, Integer, Short, Character, Byte.
 * </p>
 */
    public void setValue(Object value);


/**
 * <p>
 * Gets the value of the Monitored Attribute. The value can be obtained
 * from different parts of the module. User may choose to delegate the call
 * to getValue() to other variables.
 *
 * NOTE: It is important to make sure that the type of Object returned in
 * getvalue is same as the one specified in MonitoredAttributeInfo for this
 * attribute.
 * </p>
 * <p>
 *
 * </p>
 * <p>
 *
 * @param value is the current value for this MonitoredAttribute
 * </p>
 */
    public Object getValue();
/**
 * <p>
 * Gets the name of the Monitored Attribute.
 * </p>
 * <p>
 *
 * @param name of this Attribute
 * </p>
 */
    public String getName();
/**
 * <p>
 * If this attribute needs to be cleared, the user needs to implement this
 * method to reset the state to initial state. If the Monitored Attribute
 * doesn't change like for example (ConnectionManager High Water Mark),
 * then clearState() is a No Op.
 * </p>
 *
 */
    public void clearState();

} // end MonitoredAttribute

⏎ com/sun/corba/se/spi/monitoring/MonitoredAttribute.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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