public class MyTreeModel extends DefaultTreeModel
{
    private static final long serialVersionUID = 7522249943744455803L;
}
If I see this then I know its been written using eclipse, to turn it off go to the project's properties. In the tree follow Java Compiler->Errors/Warnings. To configure this for all projects click on Configure Workspace Settings... In the list of categories choose Potential Programming Problems and the setting for serial UIDs is top of the list, here you can it to ignore.