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 java.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ java/beans/beancontext/BeanContextServicesListener.java

/*
 * Copyright (c) 1998, 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.beans.beancontext;

import java.beans.beancontext.BeanContextServiceAvailableEvent;
import java.beans.beancontext.BeanContextServiceRevokedEvent;
import java.beans.beancontext.BeanContextServiceRevokedListener;

/**
 * The listener interface for receiving
 * <code>BeanContextServiceAvailableEvent</code> objects.
 * A class that is interested in processing a
 * <code>BeanContextServiceAvailableEvent</code> implements this interface.
 */
public interface BeanContextServicesListener extends BeanContextServiceRevokedListener {

    /**
     * The service named has been registered. getService requests for
     * this service may now be made.
     * @param bcsae the <code>BeanContextServiceAvailableEvent</code>
     */
    void serviceAvailable(BeanContextServiceAvailableEvent bcsae);
}

⏎ java/beans/beancontext/BeanContextServicesListener.java

Or download all of them as a single archive file:

File name: jre-rt-java-1.8.0_191-src.zip
File size: 6664831 bytes
Release date: 2018-10-28
Download 

⇒ JRE 8 rt.jar - javax.* Package Source Code

⇐ JRE 8 plugin.jar - Java Deploy Control Panel Plugin

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