fixed occasional nullpointer exception due to h...

fixed occasional nullpointer exception due to hashcode computation

3 files changed, 9 insertions, 2 deletions

diff --git a/sources/scala/xml/Elem.scala b/sources/scala/xml/Elem.scala
index 334344e8f6..6a6d70d1e6 100644
--- a/sources/scala/xml/Elem.scala
+++ b/sources/scala/xml/Elem.scala
@@ -46,6 +46,9 @@ case class Elem(override val prefix: String,
 
   final override def typeTag$: Int = 0;
 
+  override def hashCode(): Int = {
+    Utility.hashCode(prefix, label, attributes.hashCode(), scope.hashCode(), child);
+  }
   /** Return a new element with updated attributes
    *
    *  @param attrs
diff --git a/sources/scala/xml/Node.scala b/sources/scala/xml/Node.scala
index 9dfd1c3e6c..0bb28e1af1 100644
--- a/sources/scala/xml/Node.scala
+++ b/sources/scala/xml/Node.scala
@@ -99,7 +99,7 @@ abstract class Node extends NodeSeq {
   }
   /** returns a hashcode */
   override def hashCode(): Int;
-    //Utility.hashCode(namespace, label, attributes.hashCode(), child);
+    //Utility.hashCode(pre, label, attributes.hashCode(), child);
 
 
   /** method for NodeSeq */
diff --git a/sources/scala/xml/Utility.scala b/sources/scala/xml/Utility.scala
index ed3ef7a737..2737e75d58 100644
--- a/sources/scala/xml/Utility.scala
+++ b/sources/scala/xml/Utility.scala
@@ -138,7 +138,11 @@ object Utility extends AnyRef with parsing.TokenTests {
    * @param children
    */
   def hashCode(pre: String, label: String, attribHashCode: Int, scpeHash: Int, children: Seq[Node]) = {
-    41 * pre.hashCode() % 7 + label.hashCode() * 53 + attribHashCode * 7 + scpeHash * 31 + children.hashCode()
+    ( if(pre!=null) {41 * pre.hashCode() % 7} else {0})
+    + label.hashCode() * 53
+    + attribHashCode * 7
+    + scpeHash * 31
+    + children.hashCode()
   }
 
   /**