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/font/LayoutPath.java

/*
 * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 * (C) Copyright IBM Corp. 2005, All Rights Reserved.
 */
package java.awt.font;

import java.awt.geom.Point2D;

/**
 * LayoutPath provides a mapping between locations relative to the
 * baseline and points in user space.  Locations consist of an advance
 * along the baseline, and an offset perpendicular to the baseline at
 * the advance.  Positive values along the perpendicular are in the
 * direction that is 90 degrees clockwise from the baseline vector.
 * Locations are represented as a <code>Point2D</code>, where x is the advance and
 * y is the offset.
 *
 * @since 1.6
 */
public abstract class LayoutPath {
    /**
     * Convert a point in user space to a location relative to the
     * path. The location is chosen so as to minimize the distance
     * from the point to the path (e.g., the magnitude of the offset
     * will be smallest).  If there is more than one such location,
     * the location with the smallest advance is chosen.
     * @param point the point to convert.  If it is not the same
     * object as location, point will remain unmodified by this call.
     * @param location a <code>Point2D</code> to hold the returned location.
     * It can be the same object as point.
     * @return true if the point is associated with the portion of the
     * path preceding the location, false if it is associated with
     * the portion following.  The default, if the location is not at
     * a break or sharp bend in the path, is to return true.
     * @throws NullPointerException if point or location is null
     * @since 1.6
     */
    public abstract boolean pointToPath(Point2D point, Point2D location);

    /**
     * Convert a location relative to the path to a point in user
     * coordinates.  The path might bend abruptly or be disjoint at
     * the location's advance.  If this is the case, the value of
     * 'preceding' is used to disambiguate the portion of the path
     * whose location and slope is to be used to interpret the offset.
     * @param location a <code>Point2D</code> representing the advance (in x) and
     * offset (in y) of a location relative to the path.  If location
     * is not the same object as point, location will remain
     * unmodified by this call.
     * @param preceding if true, the portion preceding the advance
     * should be used, if false the portion after should be used.
     * This has no effect if the path does not break or bend sharply
     * at the advance.
     * @param point a <code>Point2D</code> to hold the returned point.  It can be
     * the same object as location.
     * @throws NullPointerException if location or point is null
     * @since 1.6
     */
    public abstract void pathToPoint(Point2D location, boolean preceding,
                                     Point2D point);
}

⏎ java/awt/font/LayoutPath.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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