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/swing/ComboBoxModel.java

/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.swing;

/**
 * A data model for a combo box. This interface extends <code>ListDataModel</code>
 * and adds the concept of a <i>selected item</i>. The selected item is generally
 * the item which is visible in the combo box display area.
 * <p>
 * The selected item may not necessarily be managed by the underlying
 * <code>ListModel</code>. This disjoint behavior allows for the temporary
 * storage and retrieval of a selected item in the model.
 *
 * @param <E> the type of the elements of this model
 *
 * @author Arnaud Weber
 */
public interface ComboBoxModel<E> extends ListModel<E> {

  /**
   * Set the selected item. The implementation of this  method should notify
   * all registered <code>ListDataListener</code>s that the contents
   * have changed.
   *
   * @param anItem the list object to select or <code>null</code>
   *        to clear the selection
   */
  void setSelectedItem(Object anItem);

  /**
   * Returns the selected item
   * @return The selected item or <code>null</code> if there is no selection
   */
  Object getSelectedItem();
}

⏎ javax/swing/ComboBoxModel.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

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