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/WindowsTreeUI.java

/*
 * Copyright (c) 1997, 2013, 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 java.awt.event.*;

import java.io.*;
import java.util.*;

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

import javax.swing.tree.*;

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


/**
 * A Windows tree.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases.  The current serialization support is appropriate
 * for short term storage or RMI between applications running the same
 * version of Swing.  A future release of Swing will provide support for
 * long term persistence.
 *
 * @author Scott Violet
 */
public class WindowsTreeUI extends BasicTreeUI {

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


    /**
      * Ensures that the rows identified by beginRow through endRow are
      * visible.
      */
    protected void ensureRowsAreVisible(int beginRow, int endRow) {
        if(tree != null && beginRow >= 0 && endRow < getRowCount(tree)) {
            Rectangle visRect = tree.getVisibleRect();
            if(beginRow == endRow) {
                Rectangle     scrollBounds = getPathBounds(tree, getPathForRow
                                                           (tree, beginRow));

                if(scrollBounds != null) {
                    scrollBounds.x = visRect.x;
                    scrollBounds.width = visRect.width;
                    tree.scrollRectToVisible(scrollBounds);
                }
            }
            else {
                Rectangle   beginRect = getPathBounds(tree, getPathForRow
                                                      (tree, beginRow));
                if (beginRect != null) {
                    Rectangle   testRect = beginRect;
                    int         beginY = beginRect.y;
                    int         maxY = beginY + visRect.height;

                    for(int counter = beginRow + 1; counter <= endRow; counter++) {
                        testRect = getPathBounds(tree,
                                                 getPathForRow(tree, counter));
                        if(testRect != null && (testRect.y + testRect.height) > maxY) {
                            counter = endRow;
                        }
                    }

                    if (testRect == null) {
                        return;
                    }

                    tree.scrollRectToVisible(new Rectangle(visRect.x, beginY, 1,
                                                      testRect.y + testRect.height-
                                                      beginY));
                }
            }
        }
    }

    static protected final int HALF_SIZE = 4;
    static protected final int SIZE = 9;

    /**
     * Returns the default cell renderer that is used to do the
     * stamping of each node.
     */
    protected TreeCellRenderer createDefaultCellRenderer() {
        return new WindowsTreeCellRenderer();
    }

    /**
     * The minus sign button icon
     * <p>
     * <strong>Warning:</strong>
     * Serialized objects of this class will not be compatible with
     * future Swing releases.  The current serialization support is appropriate
     * for short term storage or RMI between applications running the same
     * version of Swing.  A future release of Swing will provide support for
     * long term persistence.
     */
    public static class ExpandedIcon implements Icon, Serializable {

        static public Icon createExpandedIcon() {
            return new ExpandedIcon();
        }

        Skin getSkin(Component c) {
            XPStyle xp = XPStyle.getXP();
            return (xp != null) ? xp.getSkin(c, Part.TVP_GLYPH) : null;
        }

        public void paintIcon(Component c, Graphics g, int x, int y) {
            Skin skin = getSkin(c);
            if (skin != null) {
                skin.paintSkin(g, x, y, State.OPENED);
                return;
            }

            Color     backgroundColor = c.getBackground();

            if(backgroundColor != null)
                g.setColor(backgroundColor);
            else
                g.setColor(Color.white);
            g.fillRect(x, y, SIZE-1, SIZE-1);
            g.setColor(Color.gray);
            g.drawRect(x, y, SIZE-1, SIZE-1);
            g.setColor(Color.black);
            g.drawLine(x + 2, y + HALF_SIZE, x + (SIZE - 3), y + HALF_SIZE);
        }

        public int getIconWidth() {
            Skin skin = getSkin(null);
            return (skin != null) ? skin.getWidth() : SIZE;
        }

        public int getIconHeight() {
            Skin skin = getSkin(null);
            return (skin != null) ? skin.getHeight() : SIZE;
        }
    }

    /**
     * The plus sign button icon
     * <p>
     * <strong>Warning:</strong>
     * Serialized objects of this class will not be compatible with
     * future Swing releases.  The current serialization support is appropriate
     * for short term storage or RMI between applications running the same
     * version of Swing.  A future release of Swing will provide support for
     * long term persistence.
     */
    public static class CollapsedIcon extends ExpandedIcon {
        static public Icon createCollapsedIcon() {
            return new CollapsedIcon();
        }

        public void paintIcon(Component c, Graphics g, int x, int y) {
            Skin skin = getSkin(c);
            if (skin != null) {
                skin.paintSkin(g, x, y, State.CLOSED);
            } else {
            super.paintIcon(c, g, x, y);
            g.drawLine(x + HALF_SIZE, y + 2, x + HALF_SIZE, y + (SIZE - 3));
            }
        }
    }

    public class WindowsTreeCellRenderer extends DefaultTreeCellRenderer {

        /**
         * Configures the renderer based on the passed in components.
         * The value is set from messaging the tree with
         * <code>convertValueToText</code>, which ultimately invokes
         * <code>toString</code> on <code>value</code>.
         * The foreground color is set based on the selection and the icon
         * is set based on on leaf and expanded.
         */
        public Component getTreeCellRendererComponent(JTree tree, Object value,
                                                      boolean sel,
                                                      boolean expanded,
                                                      boolean leaf, int row,
                                                      boolean hasFocus) {
            super.getTreeCellRendererComponent(tree, value, sel,
                                               expanded, leaf, row,
                                               hasFocus);
            // Windows displays the open icon when the tree item selected.
            if (!tree.isEnabled()) {
                setEnabled(false);
                if (leaf) {
                    setDisabledIcon(getLeafIcon());
                } else if (sel) {
                    setDisabledIcon(getOpenIcon());
                } else {
                    setDisabledIcon(getClosedIcon());
                }
            }
            else {
                setEnabled(true);
                if (leaf) {
                    setIcon(getLeafIcon());
                } else if (sel) {
                    setIcon(getOpenIcon());
                } else {
                    setIcon(getClosedIcon());
                }
            }
            return this;
        }

    }

}

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