Archived:Class inheriting from Canvas should not implement a method called update() (Known Issue)
If an object has Canvas as its base class and implements a method named update(), the MIDlet in question will not function properly. This affects both S60 devices as well as S60 emulators.
If this MIDlet is executed in an S60 emulator, the emulator will exit with the following error message:
java.lang.Error: ClassFormatError: Override of final method
The reason this error is is that in the Symbian Java ME implementation the method update() of class Canvas is defined to be final, and the inheriting class cannot override a final method of the base class.
A workaround is to change the name of this method to something other than "update". You can also obfuscate the MIDlet to avoid this problem.