Index: trunk/src/com/kitfox/svg/SVGElement.java
===================================================================
--- trunk/src/com/kitfox/svg/SVGElement.java	(revision 14643)
+++ trunk/src/com/kitfox/svg/SVGElement.java	(revision 15901)
@@ -260,9 +260,10 @@
         if (this.id != null && !this.id.equals(""))
         {
+            this.id = this.id.intern();
             diagram.setElement(this.id, this);
         }
 
         String className = attrs.getValue("class");
-        this.cssClass = (className == null || className.equals("")) ? null : className;
+        this.cssClass = (className == null || className.equals("")) ? null : className.intern();
         //docRoot = helper.docRoot;
         //universe = helper.universe;
@@ -298,5 +299,5 @@
             String value = attrs.getValue(i);
 
-            presAttribs.put(name, new StyleAttribute(name, value));
+            presAttribs.put(name, new StyleAttribute(name, value == null ? null : value.intern()));
         }
     }