Add @NotNull annotation to methods to improve documentation

[jeaf-anaptecs]

Feature Description

Add @NotNull annotation to generated operations. This will not have any impact on the acctual implementation, but from a documentation perspective this make the expectations clear to users of such an operation.

Concrete type of the not null annotation should be configured in Maven configuration e.g. jakarta.annotation.Nonnull

Requirements

• Service Interfaces
• POJOs /ServiceObjects
  • SoftLink, Associations, Properties
  • get, set
  • Builder setters
  • custom operations
• NotNull for single value properties, NotEmpty for multivalue properties
• Nullable annotation for single valued properties, associations etc.