public interface ScriptHandler
This interface must be implemented in order to call Java code from
 an SVG document.
 A ScriptHandler instance is called when a 'script' element's 'type'
 attribute value is 'application/java-archive' and when the
 manifest of the jar file referenced by the 'xlink:href' attribute
 contains a 'Script-Handler' entry.  The value of this entry must be
 the classname of the ScriptHandler to call.
 This classes implementing this interface must have a default
 constructor.