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

⏎ javax/sql/ConnectionEvent.java

/*
 * Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package javax.sql;

import java.sql.SQLException;

/**
 * <P>An <code>Event</code> object that provides information about the
 * source of a connection-related event.  <code>ConnectionEvent</code>
 * objects are generated when an application closes a pooled connection
 * and when an error occurs.  The <code>ConnectionEvent</code> object
 * contains two kinds of information:
 * <UL>
 *   <LI>The pooled connection closed by the application
 *   <LI>In the case of an error event, the <code>SQLException</code>
 *       about to be thrown to the application
 * </UL>
 *
 * @since 1.4
 */

public class ConnectionEvent extends java.util.EventObject {

  /**
   * <P>Constructs a <code>ConnectionEvent</code> object initialized with
   * the given <code>PooledConnection</code> object. <code>SQLException</code>
   * defaults to <code>null</code>.
   *
   * @param con the pooled connection that is the source of the event
   * @throws IllegalArgumentException if <code>con</code> is null.
   */
  public ConnectionEvent(PooledConnection con) {
    super(con);
  }

  /**
   * <P>Constructs a <code>ConnectionEvent</code> object initialized with
   * the given <code>PooledConnection</code> object and
   * <code>SQLException</code> object.
   *
   * @param con the pooled connection that is the source of the event
   * @param ex the SQLException about to be thrown to the application
   * @throws IllegalArgumentException if <code>con</code> is null.
   */
  public ConnectionEvent(PooledConnection con, SQLException ex) {
    super(con);
    this.ex = ex;
  }

  /**
   * <P>Retrieves the <code>SQLException</code> for this
   * <code>ConnectionEvent</code> object. May be <code>null</code>.
   *
   * @return the SQLException about to be thrown or <code>null</code>
   */
  public SQLException getSQLException() { return ex; }

  /**
   * The <code>SQLException</code> that the driver will throw to the
   * application when an error occurs and the pooled connection is no
   * longer usable.
   * @serial
   */
  private SQLException ex = null;

  /**
   * Private serial version unique ID to ensure serialization
   * compatibility.
   */
  static final long serialVersionUID = -4843217645290030002L;

 }

⏎ javax/sql/ConnectionEvent.java

Or download all of them as a single archive file:

File name: jre-rt-javax-1.8.0_191-src.zip
File size: 5381005 bytes
Release date: 2018-10-28
Download 

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

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

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)