--- old/src/java.desktop/share/classes/java/awt/image/PackedColorModel.java	2016-06-02 19:15:41.388580192 +0530
+++ new/src/java.desktop/share/classes/java/awt/image/PackedColorModel.java	2016-06-02 19:15:41.032402205 +0530
@@ -27,6 +27,7 @@
 
 import java.awt.Transparency;
 import java.awt.color.ColorSpace;
+import java.util.Arrays;
 
 /**
  * The {@code PackedColorModel} class is an abstract
@@ -88,6 +89,7 @@
     int[] maskArray;
     int[] maskOffsets;
     float[] scaleFactors;
+    private volatile int hashCode;
 
     /**
      * Constructs a {@code PackedColorModel} from a color mask array,
@@ -385,19 +387,22 @@
     }
 
     /**
-     * Tests if the specified {@code Object} is an instance
-     * of {@code PackedColorModel} and equals this
+     * Tests if the specified {@code Object} equals this
      * {@code PackedColorModel}.
+     * In order to protect the symmetry property of
+     * {@code (a.equals(b) == b.equals(a))},
+     * the target object must be the same class(and not a subclass)
+     * as this object to evaluate as {equals}.
      * @param obj the {@code Object} to test for equality
      * @return {@code true} if the specified {@code Object}
-     * is an instance of {@code PackedColorModel} and equals this
-     * {@code PackedColorModel}; {@code false} otherwise.
+     * equals this {@code PackedColorModel}; {@code false} otherwise.
      */
+    @Override
     public boolean equals(Object obj) {
-        if (!(obj instanceof PackedColorModel)) {
-            return false;
-        }
-
+        /*
+         * We verify the type of argument obj in super.equals() where we check
+         * for equality of class name.
+         */
         if (!super.equals(obj)) {
             return false;
         }
@@ -412,6 +417,22 @@
         return true;
     }
 
+    /**
+     * Returns the hash code for this PackedColorModel.
+     *
+     * @return    a hash code for this PackedColorModel.
+     */
+    @Override
+    public int hashCode() {
+        int result = hashCode;
+        if (result == 0) {
+            result = super.hashCode();
+            result = 89 * result + Arrays.hashCode(this.maskArray);
+            hashCode = result;
+        }
+        return result;
+    }
+
     private static final int[] createBitsArray(int[]colorMaskArray,
                                                int alphaMask) {
         int numColors = colorMaskArray.length;