Run main class in sample 01, got error

Binding to null instances is not allowed. Use toProvider(Providers.of(null)) if this is your intended behaviour.
at net.jworkflow.WorkflowModule.configure(WorkflowModule.java:54)
Error code was module.build();
WorkflowModule module = new WorkflowModule();
module.build();

Run sample 01 and inspect WorkflowModule.configure at line 54, then trace the module.build() call from its main class. Confirm whether the sample should avoid the null binding error or explicitly support the intended null behavior; done means the sample runs successfully with the expected workflow setup.

Written by the indexing model from the issue text.