Bug 189622 DesignElementHandle.getMethods( ) shouldn't return null value
The return type of DesignElementHandle.getMethods( ) is List; if the design element handle doesn't have script methods, then it return null value. The return value is empty list will be better.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/extension/PeerExtensibilityProvider.java
{
			ElementRefValue oldRef = (ElementRefValue) oldValue;
			ReferenceValueUtil.updateReference( element, oldRef,
					(ReferenceValue) value, prop );
		}
		if ( value != null )
			extensionPropValues.put( propName, value );
		else
			extensionPropValues.remove( propName );
	}
	/**
	 * Initializes the extension element instance of <code>IReportItem</code>.
	 * 
	 * @param module
	 *            module
	 * @throws ExtendedElementException
	 *             if the extension is not found or it's failed to initialized
	 *             the extension element instance.
	 */
	public void initializeReportItem( Module module )
			throws ExtendedElementException
	{
		if ( reportItem != null )
			return;
		PeerExtensionElementDefn extDefn = (PeerExtensionElementDefn) getExtDefn( );
		if ( extDefn == null )
			throw new ExtendedElementException( element,
					ModelException.PLUGIN_ID,
					SemanticError.DESIGN_EXCEPTION_EXTENSION_NOT_FOUND, null );
		IReportItemFactory elementFactory = extDefn.getReportItemFactory( );