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/awt/peer/CheckboxPeer.java

/*
 * Copyright (c) 1995, 2014, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.awt.peer;

import java.awt.Checkbox;
import java.awt.CheckboxGroup;

/**
 * The peer interface for {@link Checkbox}.
 *
 * The peer interfaces are intended only for use in porting
 * the AWT. They are not intended for use by application
 * developers, and developers should not implement peers
 * nor invoke any of the peer methods directly on the peer
 * instances.
 */
public interface CheckboxPeer extends ComponentPeer {

    /**
     * Sets the state of the checkbox to be checked {@code true} or
     * unchecked {@code false}.
     *
     * @param state the state to set on the checkbox
     *
     * @see Checkbox#setState(boolean)
     */
    void setState(boolean state);

    /**
     * Sets the checkbox group for this checkbox. Checkboxes in one checkbox
     * group can only be selected exclusively (like radio buttons). A value
     * of {@code null} removes this checkbox from any checkbox group.
     *
     * @param g the checkbox group to set, or {@code null} when this
     *          checkbox should not be placed in any group
     *
     * @see Checkbox#setCheckboxGroup(CheckboxGroup)
     */
    void setCheckboxGroup(CheckboxGroup g);

    /**
     * Sets the label that should be displayed on the checkbox. A value of
     * {@code null} means that no label should be displayed.
     *
     * @param label the label to be displayed on the checkbox, or
     *              {@code null} when no label should be displayed.
     */
    void setLabel(String label);

}

⏎ java/awt/peer/CheckboxPeer.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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