I don't think you're showing us enough code. The exception indicates something is calling toString() on a null object, but there's nothing in what you've shown us that calls a toString() method.
Try compiling in pretty mode with full stack traces. You'll see better error information. Paul On Tue, 12 Mar 2019, 21:53 Velusamy Velu, <[email protected]> wrote: > Adding a larger screen clip. > > > [image: Screen Shot 2019-03-12 at 5.40.52 PM.png] > > > On Tuesday, March 12, 2019 at 5:48:59 PM UTC-4, Velusamy Velu wrote: >> >> Friends: >> >> I'm developing a Chemical drawing tool and have been progressing steadily >> with a lot of difficulties. My technology stack is Java 8, GWT 2.8.2, GMD >> 2.x, Eclipse Photon, running on a MacBook Pro, and Chrome | Firefox | Opera >> for testing. A limited functioning pilot is running at >> http://peruselab.com. >> >> I just ran into a trouble that I couldn't figure out on my own. Below are >> the relevant snippets of code that's causing trouble. The call (1) >> ActionHandlerMap.getHandler(action) is expected to return an instance of >> PeruseEventHandler. I expect the sequence of execution to be 1, 2, & 3. >> However, upon returning from 2 (verified with the debugger) I see the >> control going to 4 (screen clip 1) followed by throwing an exception >> (screen clip 2). Any idea what could be wrong? Your help will be greatly >> appreciated. >> >> ... >> >> PeruseEventHandler eventHandler = ActionHandlerMap.*getHandler*(action); >> // 1 >> Globals.*currentShape* = eventHandler.handle(*null*, *null*); // 3 >> ... >> >> *public* *class* ActionHandlerMap { >> >> *public* *static* *final* Map<Action, PeruseEventHandler> >> *ACTION_HANDLER_MAP* = *new* HashMap<>(); >> >> >> *static* { >> >> *ACTION_HANDLER_MAP*.put(Action.*DRAW_SINGLE_BOND*, *new* >> SingleBondDrawingHandler()); >> >> } >> >> >> *public* *static* PeruseEventHandler getHandler(Action anAction) { >> >> *return* *ACTION_HANDLER_MAP*.get(anAction); // 2 >> >> } >> >> } >> >> >> *public* *class* Globals { >> >> *public* *static* Action *action*; >> >> *public* *static* Shape *currentShape*; // 4 >> >> } >> Enter code here... >> >> >> [image: Screen Shot 2019-03-12 at 5.36.35 PM.png] >> >> Screen clip 1 >> >> >> >> [image: Screen Shot 2019-03-12 at 5.40.52 PM.png] >> >> >> >> -- > You received this message because you are subscribed to the Google Groups > "GWT Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/google-web-toolkit. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "GWT Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/google-web-toolkit. For more options, visit https://groups.google.com/d/optout.
