diff --git a/build.xml b/build.xml
index 817ea0c..db297a6 100644
--- a/build.xml
+++ b/build.xml
@@ -41,6 +41,7 @@
 
   <target name="compile" depends="-prepare" description="Compiles the code.">
     <mkdir dir="${classes.dir}"/>
+    <copy todir="${classes.dir}"><fileset dir="src/main/resources" includes="**"/></copy>
     <javac srcdir="${src.dir}" destdir="${classes.dir}" includeAntRuntime="false"
            debug="on" optimize="${build.optimize}" source="1.6" target="1.6" encoding="utf-8">
       <classpath refid="classpath"/>
@@ -63,9 +64,7 @@
     <mkdir dir="${javadoc.dir}"/>
     <javadoc windowtitle="${ant.project.name} API" doctitle="${ant.project.name} API"
              access="public" destdir="${javadoc.dir}" additionalparam="-breakiterator">
-      <packageset dir="${src.dir}">
-        <exclude name="**/impl/**"/>
-      </packageset>
+      <packageset dir="${src.dir}"/>
       <classpath refid="classpath"/>
       <link href="http://download.oracle.com/javase/1.5.0/docs/api/"/>
     </javadoc>
@@ -91,8 +90,9 @@
   <!-- todo: depend on tests target -->
   <target name="package" depends="compile" description="Compiles code and builds jar file.">
     <jar destfile="${target.dir}/${ant.project.name}.jar">
-      <fileset dir="${classes.dir}" includes="**"/>
       <fileset dir="${src.dir}" includes="**"/> <!-- for use by GWT apps -->
+      <!-- this must follow src.dir so that Platform.java is properly overwritten -->
+      <fileset dir="${classes.dir}" includes="**"/>
     </jar>
   </target>
 
diff --git a/src/main/java/pythagoras/Pythagoras.gwt.xml b/src/main/java/pythagoras/Pythagoras.gwt.xml
index 9ce0b8a..398ee65 100644
--- a/src/main/java/pythagoras/Pythagoras.gwt.xml
+++ b/src/main/java/pythagoras/Pythagoras.gwt.xml
@@ -3,4 +3,5 @@
   <source path="f"/>
   <source path="d"/>
   <source path="i"/>
+  <source path="util"/>
 </module>
diff --git a/src/main/java/pythagoras/d/AbstractDimension.java b/src/main/java/pythagoras/d/AbstractDimension.java
index c0ff06e..3c12e43 100644
--- a/src/main/java/pythagoras/d/AbstractDimension.java
+++ b/src/main/java/pythagoras/d/AbstractDimension.java
@@ -4,6 +4,8 @@
 
 package pythagoras.d;
 
+import pythagoras.util.Platform;
+
 /**
  * Provides most of the implementation of {@link IDimension}, obtaining only width and height from
  * the derived class.
@@ -17,8 +19,8 @@ public abstract class AbstractDimension implements IDimension
 
     @Override
     public int hashCode () {
-        long bits = Double.doubleToLongBits(getWidth());
-        bits += Double.doubleToLongBits(getHeight()) * 37;
+        long bits = Platform.hashCode(getWidth());
+        bits += Platform.hashCode(getHeight()) * 37;
         return (((int) bits) ^ ((int) (bits >> 32)));
     }
 
diff --git a/src/main/java/pythagoras/d/AbstractPoint.java b/src/main/java/pythagoras/d/AbstractPoint.java
index ab7a71c..116be02 100644
--- a/src/main/java/pythagoras/d/AbstractPoint.java
+++ b/src/main/java/pythagoras/d/AbstractPoint.java
@@ -4,6 +4,8 @@
 
 package pythagoras.d;
 
+import pythagoras.util.Platform;
+
 /**
  * Provides most of the implementation of {@link IPoint}, obtaining only the location from the
  * derived class.
@@ -49,9 +51,7 @@ public abstract class AbstractPoint implements IPoint
 
     @Override
     public int hashCode () {
-        long bits = Double.doubleToLongBits(getX());
-        bits += Double.doubleToLongBits(getY()) * 37;
-        return (((int) bits) ^ ((int) (bits >> 32)));
+        return Platform.hashCode(getX()) ^ Platform.hashCode(getY());
     }
 
     @Override
diff --git a/src/main/java/pythagoras/d/AbstractRectangle.java b/src/main/java/pythagoras/d/AbstractRectangle.java
index 6c8a8d8..de38ec9 100644
--- a/src/main/java/pythagoras/d/AbstractRectangle.java
+++ b/src/main/java/pythagoras/d/AbstractRectangle.java
@@ -6,6 +6,8 @@ package pythagoras.d;
 
 import java.util.NoSuchElementException;
 
+import pythagoras.util.Platform;
+
 /**
  * Provides most of the implementation of {@link IRectangle}, obtaining only the location and
  * dimensions from the derived class.
@@ -151,11 +153,8 @@ public abstract class AbstractRectangle extends RectangularShape implements IRec
 
     @Override // from Object
     public int hashCode () {
-        long bits = Double.doubleToLongBits(getX());
-        bits += Double.doubleToLongBits(getY()) * 37;
-        bits += Double.doubleToLongBits(getWidth()) * 43;
-        bits += Double.doubleToLongBits(getHeight()) * 47;
-        return (((int) bits) ^ ((int) (bits >> 32)));
+        return Platform.hashCode(getX()) ^ Platform.hashCode(getY()) ^
+            Platform.hashCode(getWidth()) ^ Platform.hashCode(getHeight());
     }
 
     @Override // from Object
diff --git a/src/main/java/pythagoras/d/AffineTransform.java b/src/main/java/pythagoras/d/AffineTransform.java
index 5f87e49..4e7fccf 100644
--- a/src/main/java/pythagoras/d/AffineTransform.java
+++ b/src/main/java/pythagoras/d/AffineTransform.java
@@ -6,6 +6,8 @@ package pythagoras.d;
 
 import java.io.Serializable;
 
+import pythagoras.util.Platform;
+
 /**
  * Represents a 2D affine transform, which performs a linear mapping that preserves the
  * straightness and parallelness of lines.
@@ -437,24 +439,17 @@ public class AffineTransform implements Cloneable, Serializable
             "[[" + m00 + ", " + m01 + ", " + m02 + "], [" + m10 + ", " + m11 + ", " + m12 + "]]";
     }
 
-    @Override
+    // @Override // can't declare @Override due to GWT
     public AffineTransform clone () {
-        try {
-            return (AffineTransform)super.clone();
-        } catch (CloneNotSupportedException e) {
-            throw new InternalError();
-        }
+        AffineTransform xform = new AffineTransform(m00, m01, m02, m10, m11, m12);
+        xform.type = this.type;
+        return xform;
     }
 
     @Override
     public int hashCode () {
-        long bits = Double.doubleToLongBits(m00);
-        bits += Double.doubleToLongBits(m01) * 37;
-        bits += Double.doubleToLongBits(m02) * 43;
-        bits += Double.doubleToLongBits(m10) * 47;
-        bits += Double.doubleToLongBits(m11) * 53;
-        bits += Double.doubleToLongBits(m12) * 59;
-        return (((int) bits) ^ ((int) (bits >> 32)));
+        return Platform.hashCode(m00) ^ Platform.hashCode(m01) ^ Platform.hashCode(m02) ^
+            Platform.hashCode(m10) ^ Platform.hashCode(m11) ^ Platform.hashCode(m12);
     }
 
     @Override
diff --git a/src/main/java/pythagoras/d/Area.java b/src/main/java/pythagoras/d/Area.java
index 6cf105d..3ad915a 100644
--- a/src/main/java/pythagoras/d/Area.java
+++ b/src/main/java/pythagoras/d/Area.java
@@ -6,6 +6,8 @@ package pythagoras.d;
 
 import java.util.NoSuchElementException;
 
+import pythagoras.util.Platform;
+
 /**
  * Stores and manipulates an enclosed area of 2D space.
  * See http://download.oracle.com/javase/6/docs/api/java/awt/geom/Area.html
@@ -277,7 +279,7 @@ public class Area implements IShape, Cloneable
         return area.isEmpty();
     }
 
-    @Override // from Cloneable
+    // @Override // can't declare @Override due to GWT
     public Area clone () {
         Area area = new Area();
         copy(this, area);
@@ -1038,11 +1040,11 @@ public class Area implements IShape, Cloneable
 
     private void copy (Area src, Area dst) {
         dst.coordsSize = src.coordsSize;
-        dst.coords = src.coords.clone();
+        dst.coords = Platform.clone(src.coords);
         dst.rulesSize = src.rulesSize;
-        dst.rules = src.rules.clone();
+        dst.rules = Platform.clone(src.rules);
         dst.moveToCount = src.moveToCount;
-        dst.offsets = src.offsets.clone();
+        dst.offsets = Platform.clone(src.offsets);
     }
 
     private int containsExact (double x, double y) {
diff --git a/src/main/java/pythagoras/d/Path.java b/src/main/java/pythagoras/d/Path.java
index b1f5fc9..1b7c910 100644
--- a/src/main/java/pythagoras/d/Path.java
+++ b/src/main/java/pythagoras/d/Path.java
@@ -6,6 +6,8 @@ package pythagoras.d;
 
 import java.util.NoSuchElementException;
 
+import pythagoras.util.Platform;
+
 /**
  * Represents a path constructed from lines and curves and which can contain subpaths.
  */
@@ -248,16 +250,9 @@ public final class Path implements IShape, Cloneable
         return new FlatteningPathIterator(getPathIterator(t), flatness);
     }
 
-    @Override
+    // @Override // can't declare @Override due to GWT
     public Path clone () {
-        try {
-            Path p = (Path)super.clone();
-            p.types = types.clone();
-            p.points = points.clone();
-            return p;
-        } catch (CloneNotSupportedException e) {
-            throw new InternalError();
-        }
+        return new Path(rule, Platform.clone(types), Platform.clone(points), typeSize, pointSize);
     }
 
     /**
@@ -293,6 +288,14 @@ public final class Path implements IShape, Cloneable
             Crossing.isInsideEvenOdd(cross);
     }
 
+    private Path (int rule, byte[] types, double[] points, int typeSize, int pointSize) {
+        this.types = types;
+        this.points = points;
+        this.typeSize = typeSize;
+        this.pointSize = pointSize;
+        setWindingRule(rule);
+    }
+
     /** An iterator over a {@link Path}. */
     protected static class Iterator implements PathIterator
     {
diff --git a/src/main/java/pythagoras/f/AbstractDimension.java b/src/main/java/pythagoras/f/AbstractDimension.java
index 69b7c08..f089519 100644
--- a/src/main/java/pythagoras/f/AbstractDimension.java
+++ b/src/main/java/pythagoras/f/AbstractDimension.java
@@ -4,6 +4,8 @@
 
 package pythagoras.f;
 
+import pythagoras.util.Platform;
+
 /**
  * Provides most of the implementation of {@link IDimension}, obtaining only width and height from
  * the derived class.
@@ -17,7 +19,7 @@ public abstract class AbstractDimension implements IDimension
 
     @Override
     public int hashCode () {
-        return Float.floatToIntBits(getWidth()) ^ Float.floatToIntBits(getHeight());
+        return Platform.hashCode(getWidth()) ^ Platform.hashCode(getHeight());
     }
 
     @Override
diff --git a/src/main/java/pythagoras/f/AbstractPoint.java b/src/main/java/pythagoras/f/AbstractPoint.java
index 2ac8ea6..5066483 100644
--- a/src/main/java/pythagoras/f/AbstractPoint.java
+++ b/src/main/java/pythagoras/f/AbstractPoint.java
@@ -4,6 +4,8 @@
 
 package pythagoras.f;
 
+import pythagoras.util.Platform;
+
 /**
  * Provides most of the implementation of {@link IPoint}, obtaining only the location from the
  * derived class.
@@ -49,7 +51,7 @@ public abstract class AbstractPoint implements IPoint
 
     @Override
     public int hashCode () {
-        return Float.floatToIntBits(getX()) ^ Float.floatToIntBits(getY());
+        return Platform.hashCode(getX()) ^ Platform.hashCode(getY());
     }
 
     @Override
diff --git a/src/main/java/pythagoras/f/AbstractRectangle.java b/src/main/java/pythagoras/f/AbstractRectangle.java
index c0a8884..6234c9b 100644
--- a/src/main/java/pythagoras/f/AbstractRectangle.java
+++ b/src/main/java/pythagoras/f/AbstractRectangle.java
@@ -6,6 +6,8 @@ package pythagoras.f;
 
 import java.util.NoSuchElementException;
 
+import pythagoras.util.Platform;
+
 /**
  * Provides most of the implementation of {@link IRectangle}, obtaining only the location and
  * dimensions from the derived class.
@@ -151,8 +153,8 @@ public abstract class AbstractRectangle extends RectangularShape implements IRec
 
     @Override // from Object
     public int hashCode () {
-        return Float.floatToIntBits(getX()) ^ Float.floatToIntBits(getY()) ^
-            Float.floatToIntBits(getWidth()) ^ Float.floatToIntBits(getHeight());
+        return Platform.hashCode(getX()) ^ Platform.hashCode(getY()) ^
+            Platform.hashCode(getWidth()) ^ Platform.hashCode(getHeight());
     }
 
     @Override // from Object
diff --git a/src/main/java/pythagoras/f/AffineTransform.java b/src/main/java/pythagoras/f/AffineTransform.java
index 34f8a12..226d93d 100644
--- a/src/main/java/pythagoras/f/AffineTransform.java
+++ b/src/main/java/pythagoras/f/AffineTransform.java
@@ -6,6 +6,8 @@ package pythagoras.f;
 
 import java.io.Serializable;
 
+import pythagoras.util.Platform;
+
 /**
  * Represents a 2D affine transform, which performs a linear mapping that preserves the
  * straightness and parallelness of lines.
@@ -436,19 +438,17 @@ public class AffineTransform implements Cloneable, Serializable
             "[[" + m00 + ", " + m01 + ", " + m02 + "], [" + m10 + ", " + m11 + ", " + m12 + "]]";
     }
 
-    @Override
+    // @Override // can't declare @Override due to GWT
     public AffineTransform clone () {
-        try {
-            return (AffineTransform)super.clone();
-        } catch (CloneNotSupportedException e) {
-            throw new InternalError();
-        }
+        AffineTransform xform = new AffineTransform(m00, m01, m02, m10, m11, m12);
+        xform.type = this.type;
+        return xform;
     }
 
     @Override
     public int hashCode () {
-        return Float.floatToIntBits(m00) ^ Float.floatToIntBits(m01) ^ Float.floatToIntBits(m02) ^
-            Float.floatToIntBits(m10) ^ Float.floatToIntBits(m11) ^ Float.floatToIntBits(m12);
+        return Platform.hashCode(m00) ^ Platform.hashCode(m01) ^ Platform.hashCode(m02) ^
+            Platform.hashCode(m10) ^ Platform.hashCode(m11) ^ Platform.hashCode(m12);
     }
 
     @Override
diff --git a/src/main/java/pythagoras/f/Area.java b/src/main/java/pythagoras/f/Area.java
index df1d0a7..b3ec4cd 100644
--- a/src/main/java/pythagoras/f/Area.java
+++ b/src/main/java/pythagoras/f/Area.java
@@ -6,6 +6,8 @@ package pythagoras.f;
 
 import java.util.NoSuchElementException;
 
+import pythagoras.util.Platform;
+
 /**
  * Stores and manipulates an enclosed area of 2D space.
  * See http://download.oracle.com/javase/6/docs/api/java/awt/geom/Area.html
@@ -277,7 +279,7 @@ public class Area implements IShape, Cloneable
         return area.isEmpty();
     }
 
-    @Override // from Cloneable
+    // @Override // can't declare @Override due to GWT
     public Area clone () {
         Area area = new Area();
         copy(this, area);
@@ -1038,11 +1040,11 @@ public class Area implements IShape, Cloneable
 
     private void copy (Area src, Area dst) {
         dst.coordsSize = src.coordsSize;
-        dst.coords = src.coords.clone();
+        dst.coords = Platform.clone(src.coords);
         dst.rulesSize = src.rulesSize;
-        dst.rules = src.rules.clone();
+        dst.rules = Platform.clone(src.rules);
         dst.moveToCount = src.moveToCount;
-        dst.offsets = src.offsets.clone();
+        dst.offsets = Platform.clone(src.offsets);
     }
 
     private int containsExact (float x, float y) {
diff --git a/src/main/java/pythagoras/f/Path.java b/src/main/java/pythagoras/f/Path.java
index 28ced8c..b8030a2 100644
--- a/src/main/java/pythagoras/f/Path.java
+++ b/src/main/java/pythagoras/f/Path.java
@@ -6,6 +6,8 @@ package pythagoras.f;
 
 import java.util.NoSuchElementException;
 
+import pythagoras.util.Platform;
+
 /**
  * Represents a path constructed from lines and curves and which can contain subpaths.
  */
@@ -248,16 +250,9 @@ public final class Path implements IShape, Cloneable
         return new FlatteningPathIterator(getPathIterator(t), flatness);
     }
 
-    @Override
+    // @Override // can't declare @Override due to GWT
     public Path clone () {
-        try {
-            Path p = (Path)super.clone();
-            p.types = types.clone();
-            p.points = points.clone();
-            return p;
-        } catch (CloneNotSupportedException e) {
-            throw new InternalError();
-        }
+        return new Path(rule, Platform.clone(types), Platform.clone(points), typeSize, pointSize);
     }
 
     /**
@@ -293,6 +288,14 @@ public final class Path implements IShape, Cloneable
             Crossing.isInsideEvenOdd(cross);
     }
 
+    private Path (int rule, byte[] types, float[] points, int typeSize, int pointSize) {
+        this.types = types;
+        this.points = points;
+        this.typeSize = typeSize;
+        this.pointSize = pointSize;
+        setWindingRule(rule);
+    }
+
     /** An iterator over a {@link Path}. */
     protected static class Iterator implements PathIterator
     {
diff --git a/src/main/java/pythagoras/util/Platform.java b/src/main/java/pythagoras/util/Platform.java
new file mode 100644
index 0000000..9576e7b
--- /dev/null
+++ b/src/main/java/pythagoras/util/Platform.java
@@ -0,0 +1,54 @@
+//
+// Pythagoras - a collection of geometry classes
+// http://github.com/samskivert/pythagoras
+
+package pythagoras.util;
+
+/**
+ * Handles differences between the JDK and GWT platforms.
+ */
+public class Platform
+{
+    /**
+     * Returns a hash code for the supplied float value.
+     */
+    public static int hashCode (float f1) {
+        return Float.floatToIntBits(f1);
+    }
+
+    /**
+     * Returns a hash code for the supplied double value.
+     */
+    public static int hashCode (double d1) {
+        long bits = Double.doubleToLongBits(d1);
+        return (int)(bits ^ (bits >>> 32));
+    }
+
+    /**
+     * Clones the supplied array of bytes.
+     */
+    public static byte[] clone (byte[] values) {
+        return values.clone();
+    }
+
+    /**
+     * Clones the supplied array of ints.
+     */
+    public static int[] clone (int[] values) {
+        return values.clone();
+    }
+
+    /**
+     * Clones the supplied array of floats.
+     */
+    public static float[] clone (float[] values) {
+        return values.clone();
+    }
+
+    /**
+     * Clones the supplied array of doubles.
+     */
+    public static double[] clone (double[] values) {
+        return values.clone();
+    }
+}
diff --git a/src/main/resources/pythagoras/util/Platform.java b/src/main/resources/pythagoras/util/Platform.java
new file mode 100644
index 0000000..e916471
--- /dev/null
+++ b/src/main/resources/pythagoras/util/Platform.java
@@ -0,0 +1,63 @@
+//
+// Pythagoras - a collection of geometry classes
+// http://github.com/samskivert/pythagoras
+
+package pythagoras.util;
+
+/**
+ * A platform instance that's used when running in GWT. Note that this is copied over top of the
+ * JDK implementation in the pythagoras.jar file, so this is never actually compiled to bytecode.
+ * Thus be careful when making changes to this file.
+ */
+public class Platform
+{
+    /**
+     * Returns a hash code for the supplied float value.
+     */
+    public static int hashCode (float f1) {
+        return (int)f1; // alas nothing better can be done in JavaScript
+    }
+
+    /**
+     * Returns a hash code for the supplied double value.
+     */
+    public static int hashCode (double d1) {
+        return (int)d1; // alas nothing better can be done in JavaScript
+    }
+
+    /**
+     * Clones the supplied array of bytes.
+     */
+    public static byte[] clone (byte[] values) {
+        byte[] nvalues = new byte[values.length];
+        System.arraycopy(values, 0, nvalues, 0, values.length);
+        return nvalues;
+    }
+
+    /**
+     * Clones the supplied array of ints.
+     */
+    public static int[] clone (int[] values) {
+        int[] nvalues = new int[values.length];
+        System.arraycopy(values, 0, nvalues, 0, values.length);
+        return nvalues;
+    }
+
+    /**
+     * Clones the supplied array of floats.
+     */
+    public static float[] clone (float[] values) {
+        float[] nvalues = new float[values.length];
+        System.arraycopy(values, 0, nvalues, 0, values.length);
+        return nvalues;
+    }
+
+    /**
+     * Clones the supplied array of doubles.
+     */
+    public static double[] clone (double[] values) {
+        double[] nvalues = new double[values.length];
+        System.arraycopy(values, 0, nvalues, 0, values.length);
+        return nvalues;
+    }
+}