Calendar in midp

[Kamil]

Hello

I'm currently writing an application under MIDP 1.0 profile.
The problem appears, when I'am extending a java.util.Calendar class by
another class A and then I'm creating an instance of this class.

During runtime there is called an exception
java/lang/AbstractMethodError: computeFields

Calendar class doesn't have required methods computeFields() /
computeTime(). The only functions it has are private calculateFields() /
calculateTime(), so you can't in the subclass A add computeFields() /
computeTime(), which uses metioned above methods. (If I add
computeFields() / computeTime() that do nothing, the program doesn't
crash but the class A doesn't work properly either.)

Has anyone similar problem?
I would be grateful for some clues.

Greetz
Kamil