Buggy code:
//* ===========================================================  * JFreeChart : a free chart library for the Java(tm) platform  * ===========================================================  *  * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.  *  * Project Info:  http: *  * This library is free software; you can redistribute it and//or modify it  * under the terms of the GNU Lesser General Public License as published by  * the Free Software Foundation; either version 2.1 of the License, or  * (at your option) any later version.  *  * This library is distributed in the hope that it will be useful, but  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public  * License for more details.  *  * You should have received a copy of the GNU Lesser General Public  * License along with this library; if not, write to the Free Software  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,  * USA.  *  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.  * in the United States and other countries.]  *  * -------------------  * ShapeUtilities.java  * -------------------  * (C)opyright 2003-2008, by Object Refinery Limited and Contributors.  *  * Original Author:  David Gilbert (for Object Refinery Limited);  * Contributor(s):   -;  *  * Changes  * -------  * 13-Aug-2003 : Version 1 (DG);  * 16-Mar-2004 : Moved rotateShape() from RefineryUtilities.java to here (DG);  * 13-May-2004 : Added new shape creation methods (DG);  * 30-Sep-2004 : Added createLineRegion() method (DG);  *               Moved drawRotatedShape() method from RefineryUtilities class  *               to this class (DG);  * 04-Oct-2004 : Renamed ShapeUtils --> ShapeUtilities (DG);  * 26-Oct-2004 : Added a method to test the equality of two Line2D  *               instances (DG);  * 10-Nov-2004 : Added new translateShape() and equal(Ellipse2D, Ellipse2D)  *               methods (DG);  * 11-Nov-2004 : Renamed translateShape() --> createTranslatedShape() (DG);  * 07-Jan-2005 : Minor Javadoc fix (DG);  * 11-Jan-2005 : Removed deprecated code in preparation for 1.0.0 release (DG);  * 21-Jan-2005 : Modified return type of RectangleAnchor.coordinates()  *               method (DG);  * 22-Feb-2005 : Added equality tests for Arc2D and GeneralPath (DG);  * 16-Mar-2005 : Fixed bug where equal(Shape, Shape) fails for two Polygon  *               instances (DG);  * 20-Jun-2007 : Copied from JCommon (DG);  * 02-Jun-2008 : Fixed bug in equal(GeneralPath, GeneralPath) (DG);  *  *//  package org.jfree.chart.util;  import java.awt.Graphics2D; import java.awt.Polygon; import java.awt.Shape; import java.awt.geom.AffineTransform; import java.awt.geom.Arc2D; import java.awt.geom.Ellipse2D; import java.awt.geom.GeneralPath; import java.awt.geom.Line2D; import java.awt.geom.PathIterator; import java.awt.geom.Point2D; import java.awt.geom.Rectangle2D; import java.util.Arrays;  //**  * Utility methods for {@link Shape} objects.  *// public class ShapeUtilities {      //**      * Prevents instantiation.      *//     private ShapeUtilities() {     }      //**      * Returns a clone of the specified shape, or <code>null<//code>.  At the      * current time, this method supports cloning for instances of      * <code>Line2D<//code>, <code>RectangularShape<//code>, <code>Area<//code>      * and <code>GeneralPath<//code>.      * <p>      * <code>RectangularShape<//code> includes <code>Arc2D<//code>,      * <code>Ellipse2D<//code>, <code>Rectangle2D<//code>,      * <code>RoundRectangle2D<//code>.      *      * @param shape  the shape to clone (<code>null<//code> permitted,      *               returns <code>null<//code>).      *      * @return A clone or <code>null<//code>.      *//     public static Shape clone(Shape shape) {         if (shape instanceof Cloneable) {             try {                 return (Shape) ObjectUtilities.clone(shape);             }             catch (CloneNotSupportedException cnse) {             }         }         Shape result = null;         return result;     }      //**      * Tests two shapes for equality.  If both shapes are <code>null<//code>,      * this method will return <code>true<//code>.      * <p>      * In the current implementation, the following shapes are supported:      * <code>Ellipse2D<//code>, <code>Line2D<//code> and <code>Rectangle2D<//code>      * (implicit).      *      * @param s1  the first shape (<code>null<//code> permitted).      * @param s2  the second shape (<code>null<//code> permitted).      *      * @return A boolean.      *//     public static boolean equal(Shape s1, Shape s2) {         if (s1 instanceof Line2D && s2 instanceof Line2D) {             return equal((Line2D) s1, (Line2D) s2);         }         else if (s1 instanceof Ellipse2D && s2 instanceof Ellipse2D) {             return equal((Ellipse2D) s1, (Ellipse2D) s2);         }         else if (s1 instanceof Arc2D && s2 instanceof Arc2D) {             return equal((Arc2D) s1, (Arc2D) s2);         }         else if (s1 instanceof Polygon && s2 instanceof Polygon) {             return equal((Polygon) s1, (Polygon) s2);         }         else if (s1 instanceof GeneralPath && s2 instanceof GeneralPath) {             return equal((GeneralPath) s1, (GeneralPath) s2);         }         else {                         return ObjectUtilities.equal(s1, s2);         }     }      //**      * Compares two lines are returns <code>true<//code> if they are equal or      * both <code>null<//code>.      *      * @param l1  the first line (<code>null<//code> permitted).      * @param l2  the second line (<code>null<//code> permitted).      *      * @return A boolean.      *//     public static boolean equal(Line2D l1, Line2D l2) {         if (l1 == null) {             return (l2 == null);         }         if (l2 == null) {             return false;         }         if (!l1.getP1().equals(l2.getP1())) {             return false;         }         if (!l1.getP2().equals(l2.getP2())) {             return false;         }         return true;     }      //**      * Compares two ellipses and returns <code>true<//code> if they are equal or      * both <code>null<//code>.      *      * @param e1  the first ellipse (<code>null<//code> permitted).      * @param e2  the second ellipse (<code>null<//code> permitted).      *      * @return A boolean.      *//     public static boolean equal(Ellipse2D e1, Ellipse2D e2) {         if (e1 == null) {             return (e2 == null);         }         if (e2 == null) {             return false;         }         if (!e1.getFrame().equals(e2.getFrame())) {             return false;         }         return true;     }      //**      * Compares two arcs and returns <code>true<//code> if they are equal or      * both <code>null<//code>.      *      * @param a1  the first arc (<code>null<//code> permitted).      * @param a2  the second arc (<code>null<//code> permitted).      *      * @return A boolean.      *//     public static boolean equal(Arc2D a1, Arc2D a2) {         if (a1 == null) {             return (a2 == null);         }         if (a2 == null) {             return false;         }         if (!a1.getFrame().equals(a2.getFrame())) {             return false;         }         if (a1.getAngleStart() != a2.getAngleStart()) {             return false;         }         if (a1.getAngleExtent() != a2.getAngleExtent()) {             return false;         }         if (a1.getArcType() != a2.getArcType()) {             return false;         }         return true;     }      //**      * Tests two polygons for equality.  If both are <code>null<//code> this      * method returns <code>true<//code>.      *      * @param p1  polygon 1 (<code>null<//code> permitted).      * @param p2  polygon 2 (<code>null<//code> permitted).      *      * @return A boolean.      *//     public static boolean equal(Polygon p1, Polygon p2) {         if (p1 == null) {             return (p2 == null);         }         if (p2 == null) {             return false;         }         if (p1.npoints != p2.npoints) {             return false;         }         if (!Arrays.equals(p1.xpoints, p2.xpoints)) {             return false;         }         if (!Arrays.equals(p1.ypoints, p2.ypoints)) {             return false;         }         return true;     }      //**      * Tests two polygons for equality.  If both are <code>null<//code> this      * method returns <code>true<//code>.      *      * @param p1  path 1 (<code>null<//code> permitted).      * @param p2  path 2 (<code>null<//code> permitted).      *      * @return A boolean.      *//     public static boolean equal(GeneralPath p1, GeneralPath p2) {         if (p1 == null) {             return (p2 == null);         }         if (p2 == null) {             return false;         }         if (p1.getWindingRule() != p2.getWindingRule()) {             return false;         }         PathIterator iterator1 = p1.getPathIterator(null);         <START_BUG> PathIterator iterator2 = p1.getPathIterator(null); <END_BUG>         double[] d1 = new double[6];         double[] d2 = new double[6];         boolean done = iterator1.isDone() && iterator2.isDone();         while (!done) {             if (iterator1.isDone() != iterator2.isDone()) {                 return false;             }             int seg1 = iterator1.currentSegment(d1);             int seg2 = iterator2.currentSegment(d2);             if (seg1 != seg2) {                 return false;             }             if (!Arrays.equals(d1, d2)) {                 return false;             }             iterator1.next();             iterator2.next();             done = iterator1.isDone() && iterator2.isDone();         }         return true;     }      //**      * Creates and returns a translated shape.      *      * @param shape  the shape (<code>null<//code> not permitted).      * @param transX  the x translation (in Java2D space).      * @param transY  the y translation (in Java2D space).      *      * @return The translated shape.      *//     public static Shape createTranslatedShape(Shape shape,                                               double transX,                                               double transY) {         if (shape == null) {             throw new IllegalArgumentException("Null 'shape' argument.");         }         AffineTransform transform = AffineTransform.getTranslateInstance(                 transX, transY);         return transform.createTransformedShape(shape);     }      //**      * Translates a shape to a new location such that the anchor point      * (relative to the rectangular bounds of the shape) aligns with the      * specified (x, y) coordinate in Java2D space.      *      * @param shape  the shape (<code>null<//code> not permitted).      * @param anchor  the anchor (<code>null<//code> not permitted).      * @param locationX  the x-coordinate (in Java2D space).      * @param locationY  the y-coordinate (in Java2D space).      *      * @return A new and translated shape.      *//     public static Shape createTranslatedShape(Shape shape,                                               RectangleAnchor anchor,                                               double locationX,                                               double locationY) {         if (shape == null) {             throw new IllegalArgumentException("Null 'shape' argument.");         }         if (anchor == null) {             throw new IllegalArgumentException("Null 'anchor' argument.");         }         Point2D anchorPoint = RectangleAnchor.coordinates(shape.getBounds2D(),                 anchor);         AffineTransform transform = AffineTransform.getTranslateInstance(                 locationX - anchorPoint.getX(), locationY - anchorPoint.getY());         return transform.createTransformedShape(shape);     }      //**      * Rotates a shape about the specified coordinates.      *      * @param base  the shape (<code>null<//code> permitted, returns      *              <code>null<//code>).      * @param angle  the angle (in radians).      * @param x  the x coordinate for the rotation point (in Java2D space).      * @param y  the y coordinate for the rotation point (in Java2D space).      *      * @return the rotated shape.      *//     public static Shape rotateShape(Shape base, double angle,                                     float x, float y) {         if (base == null) {             return null;         }         AffineTransform rotate = AffineTransform.getRotateInstance(angle, x, y);         Shape result = rotate.createTransformedShape(base);         return result;     }      //**      * Draws a shape with the specified rotation about <code>(x, y)<//code>.      *      * @param g2  the graphics device (<code>null<//code> not permitted).      * @param shape  the shape (<code>null<//code> not permitted).      * @param angle  the angle (in radians).      * @param x  the x coordinate for the rotation point.      * @param y  the y coordinate for the rotation point.      *//     public static void drawRotatedShape(Graphics2D g2, Shape shape,                                         double angle, float x, float y) {          AffineTransform saved = g2.getTransform();         AffineTransform rotate = AffineTransform.getRotateInstance(angle, x, y);         g2.transform(rotate);         g2.draw(shape);         g2.setTransform(saved);      }      //** A useful constant used internally. *//     private static final float SQRT2 = (float) Math.pow(2.0, 0.5);      //**      * Creates a diagonal cross shape.      *      * @param l  the length of each 'arm'.      * @param t  the thickness.      *      * @return A diagonal cross shape.      *//     public static Shape createDiagonalCross(float l, float t) {         GeneralPath p0 = new GeneralPath();         p0.moveTo(-l - t, -l + t);         p0.lineTo(-l + t, -l - t);         p0.lineTo(0.0f, -t * SQRT2);         p0.lineTo(l - t, -l - t);         p0.lineTo(l + t, -l + t);         p0.lineTo(t * SQRT2, 0.0f);         p0.lineTo(l + t, l - t);         p0.lineTo(l - t, l + t);         p0.lineTo(0.0f, t * SQRT2);         p0.lineTo(-l + t, l + t);         p0.lineTo(-l - t, l - t);         p0.lineTo(-t * SQRT2, 0.0f);         p0.closePath();         return p0;     }      //**      * Creates a diagonal cross shape.      *      * @param l  the length of each 'arm'.      * @param t  the thickness.      *      * @return A diagonal cross shape.      *//     public static Shape createRegularCross(float l, float t) {         GeneralPath p0 = new GeneralPath();         p0.moveTo(-l, t);         p0.lineTo(-t, t);         p0.lineTo(-t, l);         p0.lineTo(t, l);         p0.lineTo(t, t);         p0.lineTo(l, t);         p0.lineTo(l, -t);         p0.lineTo(t, -t);         p0.lineTo(t, -l);         p0.lineTo(-t, -l);         p0.lineTo(-t, -t);         p0.lineTo(-l, -t);         p0.closePath();         return p0;     }      //**      * Creates a diamond shape.      *      * @param s  the size factor (equal to half the height of the diamond).      *      * @return A diamond shape.      *//     public static Shape createDiamond(float s) {         GeneralPath p0 = new GeneralPath();         p0.moveTo(0.0f, -s);         p0.lineTo(s, 0.0f);         p0.lineTo(0.0f, s);         p0.lineTo(-s, 0.0f);         p0.closePath();         return p0;     }      //**      * Creates a triangle shape that points upwards.      *      * @param s  the size factor (equal to half the height of the triangle).      *      * @return A triangle shape.      *//     public static Shape createUpTriangle(float s) {         GeneralPath p0 = new GeneralPath();         p0.moveTo(0.0f, -s);         p0.lineTo(s, s);         p0.lineTo(-s, s);         p0.closePath();         return p0;     }      //**      * Creates a triangle shape that points downwards.      *      * @param s  the size factor (equal to half the height of the triangle).      *      * @return A triangle shape.      *//     public static Shape createDownTriangle(float s) {         GeneralPath p0 = new GeneralPath();         p0.moveTo(0.0f, s);         p0.lineTo(s, -s);         p0.lineTo(-s, -s);         p0.closePath();         return p0;     }      //**      * Creates a region surrounding a line segment by 'widening' the line      * segment.  A typical use for this method is the creation of a      * 'clickable' region for a line that is displayed on-screen.      *      * @param line  the line (<code>null<//code> not permitted).      * @param width  the width of the region.      *      * @return A region that surrounds the line.      *//     public static Shape createLineRegion(Line2D line, float width) {         GeneralPath result = new GeneralPath();         float x1 = (float) line.getX1();         float x2 = (float) line.getX2();         float y1 = (float) line.getY1();         float y2 = (float) line.getY2();         if ((x2 - x1) != 0.0) {             double theta = Math.atan((y2 - y1) // (x2 - x1));             float dx = (float) Math.sin(theta) * width;             float dy = (float) Math.cos(theta) * width;             result.moveTo(x1 - dx, y1 + dy);             result.lineTo(x1 + dx, y1 - dy);             result.lineTo(x2 + dx, y2 - dy);             result.lineTo(x2 - dx, y2 + dy);             result.closePath();         }         else {                         result.moveTo(x1 - width // 2.0f, y1);             result.lineTo(x1 + width // 2.0f, y1);             result.lineTo(x2 + width // 2.0f, y2);             result.lineTo(x2 - width // 2.0f, y2);             result.closePath();         }         return result;     }      //**      * Returns a point based on (x, y) but constrained to be within the bounds      * of a given rectangle.      *      * @param x  the x-coordinate.      * @param y  the y-coordinate.      * @param area  the constraining rectangle (<code>null<//code> not      *              permitted).      *      * @return A point within the rectangle.      *      * @throws NullPointerException if <code>area<//code> is <code>null<//code>.      *//     public static Point2D getPointInRectangle(double x, double y,                                               Rectangle2D area) {          x = Math.max(area.getMinX(), Math.min(x, area.getMaxX()));         y = Math.max(area.getMinY(), Math.min(y, area.getMaxY()));         return new Point2D.Double(x, y);      }      //**      * Checks, whether the given rectangle1 fully contains rectangle 2      * (even if rectangle 2 has a height or width of zero!).      *      * @param rect1  the first rectangle.      * @param rect2  the second rectangle.      *      * @return A boolean.      *//     public static boolean contains(Rectangle2D rect1, Rectangle2D rect2) {          double x0 = rect1.getX();         double y0 = rect1.getY();         double x = rect2.getX();         double y = rect2.getY();         double w = rect2.getWidth();         double h = rect2.getHeight();          return ((x >= x0) && (y >= y0)                 && ((x + w) <= (x0 + rect1.getWidth()))                 && ((y + h) <= (y0 + rect1.getHeight())));      }       //**      * Checks, whether the given rectangle1 fully contains rectangle 2      * (even if rectangle 2 has a height or width of zero!).      *      * @param rect1  the first rectangle.      * @param rect2  the second rectangle.      *      * @return A boolean.      *//     public static boolean intersects(Rectangle2D rect1, Rectangle2D rect2) {        double x0 = rect1.getX();       double y0 = rect1.getY();        double x = rect2.getX();       double width = rect2.getWidth();       double y = rect2.getY();       double height = rect2.getHeight();       return (x + width >= x0 && y + height >= y0 && x <= x0 + rect1.getWidth()               && y <= y0 + rect1.getHeight());     } } 


Fix:
PathIterator iterator2 = p2.getPathIterator(null);