Avoiding internal APIs
The Java API allows you to use the same Java types that you can use in Gosu. However, Guidewire specifies some methods and fields on these types for internal use only, and unsupported for customer use. In Gosu, these internal API methods and fields are hidden, and use of them triggers a compilation error. In Java, when you are using your own IDE separate from Studio, internal APIs are visible even though unsupported.
Guidewire indicates internal API methods and properties with the annotation @gw.lang.InternalAPI.
If you use IntelliJ IDEA as your Java IDE, configure the IDE to flag inappropriate uses of internal APIs as warnings. Your copy of PolicyCenter Studio includes a code inspection you can use. See Java IDE inspections that flag unsupported internal APIs.
