| no valid constructor

Hi there,

sometimes i am geeting this strange exception while using my vaadin application:

SEVERE: Exception loading sessions from persistent storage de.clement.ffl.client.modules.welcome.HomeModule; de.clement.ffl.client.modules.welcome.HomeModule; no valid constructor

Can anybody help me, what i am doing wrong?


seems that the base class needed to be Serializable

I guess your application server is configured to serialize sessions (possibly on exit or for clustering) and de-serialize them later. If so, all classes referenced from the session should be serializable.

Note that if for server startup, failure to deserialize should (on most servers) just cause a new session to be created, and the message can be treated as a warning.