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

⏎ com/sun/java/swing/plaf/windows/WindowsToolBarSeparatorUI.java

/*
 * Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package com.sun.java.swing.plaf.windows;

import java.awt.*;

import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.basic.*;
import javax.swing.*;

import static com.sun.java.swing.plaf.windows.TMSchema.Part;
import static com.sun.java.swing.plaf.windows.XPStyle.Skin;


/**
 * Draws Windows toolbar separators.
 * <p>
 *
 * @author Mark Davidson
 */
public class WindowsToolBarSeparatorUI extends BasicToolBarSeparatorUI {

    public static ComponentUI createUI( JComponent c ) {
        return new WindowsToolBarSeparatorUI();
    }

    public Dimension getPreferredSize(JComponent c) {
        Dimension size = ((JToolBar.Separator)c).getSeparatorSize();

        if (size != null) {
            size = size.getSize();
        } else {
            size = new Dimension(6, 6);
            XPStyle xp = XPStyle.getXP();
            if (xp != null) {
                boolean vertical = ((JSeparator)c).getOrientation() == SwingConstants.VERTICAL;
                Part part = vertical ? Part.TP_SEPARATOR : Part.TP_SEPARATORVERT;
                Skin skin = xp.getSkin(c, part);
                size.width = skin.getWidth();
                size.height = skin.getHeight();
            }

            if (((JSeparator)c).getOrientation() == SwingConstants.VERTICAL) {
                size.height = 0;
            } else {
                size.width = 0;
            }
        }
        return size;
    }

    public Dimension getMaximumSize(JComponent c) {
        Dimension pref = getPreferredSize(c);
        if (((JSeparator)c).getOrientation() == SwingConstants.VERTICAL) {
            return new Dimension(pref.width, Short.MAX_VALUE);
        } else {
            return new Dimension(Short.MAX_VALUE, pref.height);
        }
    }

    public void paint( Graphics g, JComponent c ) {
        boolean vertical = ((JSeparator)c).getOrientation() == SwingConstants.VERTICAL;
        Dimension size = c.getSize();

        XPStyle xp = XPStyle.getXP();
        if (xp != null) {
            Part part = vertical ? Part.TP_SEPARATOR : Part.TP_SEPARATORVERT;
            Skin skin = xp.getSkin(c, part);

            int dx = vertical ? (size.width - skin.getWidth()) / 2 : 0;
            int dy = vertical ? 0 : (size.height - skin.getHeight()) / 2;
            int dw = vertical ? skin.getWidth() : size.width;
            int dh = vertical ? size.height : skin.getHeight();
            skin.paintSkin(g, dx, dy, dw, dh, null);
        } else {

        Color temp = g.getColor();

        UIDefaults table = UIManager.getLookAndFeelDefaults();

        Color shadow = table.getColor("ToolBar.shadow");
        Color highlight = table.getColor("ToolBar.highlight");

        if (vertical) {
            int x = (size.width / 2) - 1;
            g.setColor(shadow);
            g.drawLine(x, 2, x, size.height - 2);

            g.setColor(highlight);
            g.drawLine(x + 1, 2, x + 1, size.height - 2);
        } else {
            int y = (size.height / 2) - 1;
            g.setColor(shadow);
            g.drawLine(2, y, size.width - 2, y);
            g.setColor(highlight);
            g.drawLine(2, y + 1, size.width - 2, y + 1);
        }
        g.setColor(temp);
        }
    }
}

⏎ com/sun/java/swing/plaf/windows/WindowsToolBarSeparatorUI.java

Or download all of them as a single archive file:

File name: jre-rt-com-1.8.0_191-src.zip
File size: 8099783 bytes
Release date: 2018-10-28
Download 

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