If you use static methods in a helper class there's no problem. If you use static methods in your bean class directly there could be a problem, depending on your container implementation. The countainer is allowed to subclass your bean and could miss to take in count that you could made a static class.
Remark: don't use static members in helper classes!!! (they have tha same effect as in your bean class).
Using static *final* variables is ok (as long as it is not a final reference to a modifiable class instance!). e.g. this would be ok: static final int ONE = 1; but this would not: static final StringBuffermsg = new StringBuffer();