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/lang/ref/WeakReference.java

/*
 * Copyright (c) 1997, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.lang.ref;


/**
 * Weak reference objects, which do not prevent their referents from being
 * made finalizable, finalized, and then reclaimed.  Weak references are most
 * often used to implement canonicalizing mappings.
 *
 * <p> Suppose that the garbage collector determines at a certain point in time
 * that an object is <a href="package-summary.html#reachability">weakly
 * reachable</a>.  At that time it will atomically clear all weak references to
 * that object and all weak references to any other weakly-reachable objects
 * from which that object is reachable through a chain of strong and soft
 * references.  At the same time it will declare all of the formerly
 * weakly-reachable objects to be finalizable.  At the same time or at some
 * later time it will enqueue those newly-cleared weak references that are
 * registered with reference queues.
 *
 * @author   Mark Reinhold
 * @since    1.2
 */

public class WeakReference<T> extends Reference<T> {

    /**
     * Creates a new weak reference that refers to the given object.  The new
     * reference is not registered with any queue.
     *
     * @param referent object the new weak reference will refer to
     */
    public WeakReference(T referent) {
        super(referent);
    }

    /**
     * Creates a new weak reference that refers to the given object and is
     * registered with the given queue.
     *
     * @param referent object the new weak reference will refer to
     * @param q the queue with which the reference is to be registered,
     *          or <tt>null</tt> if registration is not required
     */
    public WeakReference(T referent, ReferenceQueue<? super T> q) {
        super(referent, q);
    }

}

⏎ java/lang/ref/WeakReference.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 

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