[BUG] isGetters of generated Java POJOs get skipped by Jackson when Optional booleans are used

[andreas-schilling]

Describe the bug
If an Aspect model contains optional booleans, the Java POJO generator builds an accessor like for regular booleans using the isGetter naming scheme:

public Optional<Boolean> isHidden() {
  return this.hidden;
}

During visibility detection Jackson however does two checks:

• check the name matches the isGetter convention (which it does)
• check whether the return type is boolean (not the case)

This results in the field becoming omitted from the payload.

Where
java-pojo-getter-lib.vm

Possible fixes
Multiple solutions exist to solve this issue:

1. use the default getter naming scheme in such a case (in this example name the method getHidden)
2. add an additional @JsonProperty annotation (simply with the same name applied) if the boolean is wrapped inside an Optional

Most likely the first option is not what most people would expect. The second option might be confusing to see when someone looks at the generated code, because at first glance it does not make sense to apply a name "override" that does not change anything in terms of property naming.

Immediate fix
As of now, the problem is most easily fixed using a Jackson mixin with a custom Jackson Module:

public abstract class MyPojoMixin {
   @JsonProperty(value = "hidden")
   abstract public Optional<Boolean> isHidden();
}

...

setMixInAnnotation( MyPojo.class, MyPojoMixin.class );

[github-actions]

Release v2.4.2 addresses this.