Any way to handle map object when generating schema

[PeterFan89]

I'm using annotation to generate graphql schema. However, it didn't work when the annotation handle map object. For example, I put the @GraphQLField on the field which type is like Map<Integer, ObjectA> and also have @GraphQLField on the field inside the object. Then I print the schema but cannot find the ObjectA type in my schema. Is there any way I can handle map object?