CustomComponent and UI class

Hello to everybody.
I’m new to this forum and vaadin.

I’m using vaadin 7.0.4 and get some error while using it. Can you help me please.

I’m trying to add class which extends UI class to the rootUI class which extends CustomComponent class.
I’m doing this in this way: rootUI.getContent().addComponent(new CalendarTest());
CalendarTest is the class which extends the UI class.

The problem is that I’m getting on my console: "
Component must be attached to a session when getConnectorId() is called for the first time
" and in application:

Communication problem
Take note of any unsaved data, and click here to continue.(SyntaxError) : Unexpected token for - Original JSON-text:{“changes”:[[“change”,{“pid”:“106”},[“38”,{“id”:“106”,“locale”:“ru”,“strict”:true,“wn”:false,“parsable”:true,“v”:{“day”:29,“month”:5,“year”:2013}}]
],[“change”,{“pid”:“107”},[“38”,{“id”:“107”,“locale”:“ru”,“strict”:true,“wn”:false,“parsable”:true,“v”:{“day”:-1,“month”:-1,“year”:-1}}]
]for(;;);[{“changes”:[]
, “meta” : {“appError”: {“caption”:“Internal error”,“message” : “Please notify the administrator.Take note of any unsaved data, and click here</u> to continue.”,“url” : null}}, “resources”: {}, “locales”:[]}

You can’t add an UI into an other UI - the UI is the entry point to your application, and not an visual component. Add the CustomComponent to the UI that you call “root” instead.

Thank you. Solved the problem by extending not the UI class. Used CustomComponent in place of UI and changed some code inside.

Very interesting framework… Starting to “fall in love”…