Content in model of a Component link returns null in Java + DXA

Question

I have a Schema with a Component link. The linked Component is a content of RTF fields. I have a Schema typeOnlineForm (rootname: OnlineForm) and schema field webMessage is the Component link field type webMessage (xmlName: webMessage) is a Component link of multiple values of General Page Content (rootname: GeneralPageContent) Schema type General Page Content is a Schema containing a field fullPageContent (which is embedded Schema of Paragraph5Level (rootname:Paragraph5Level) and so on. It will be more clearer with the model.

1. OnlineForm:

   @SemanticEntity(entityName = "OnlineForm", vocabulary = SDL_CORE, prefix = "of")
   public class OnlineForm extends AbstractEntityModel {
   
       @SemanticProperty("of:webMessage"),
       private GeneralPageContent webMessage;
   }
   

2. GeneralPageContent

   @SemanticEntity(entityName = "GeneralPageContent", vocabulary = SDL_CORE, prefix = "gp")
   public class GeneralPageContent extends AbstractEntityModel {
   
       @SemanticProperty("gp:fullPageContent")
       @JsonProperty("FullPageContent")
       private List<Paragraph5Level> fullPageContent;
   }
   

3. Paragraph5Level

   @SemanticEntity(entityName = "Paragraph5Level", vocabulary = SDL_CORE, prefix = "pl") 
   public class Paragraph5Level  extends AbstractEntityModel {
   
       @SemanticProperty("pl:heading")
       @JsonProperty("Heading")
       private String heading;
   
       @SemanticProperty("pl:paraContent")
       @JsonProperty("ParaContent")
       private List<RichText> paraContent;
   
       @SemanticProperty("pl:subParagraph")
       @JsonProperty("SubParagraph")
       private List<SubParagraphLevel2> subParagraph;
   }
   

When I preview the Component, I can see the Component link as seen below. (See webMessage and fullPageContent below.

"title": "Feedback",
"adminEmailAddress": "test@gmail.com",
"webMessage": {
    "$type": "EntityModelData",
    "Id": "9425",
    "ComponentTemplate": {
        "Id": "169",
        "RevisionDate": "0001-01-01T00:00:00"
     },
     "Folder": {
         "Id": "2163",
         "Title": "Web Messages"
     },
     "Content": {
         "fullPageContent": {
             "$type": "ContentModelData",
             "heading": "Your request has been received and a customer service representative will contact you shortly."
         }
     },
     "SchemaId": "416"
},
"formFields": { ...

But in the controller when I call model.getWebMessage, this returns nullPointerException.