how to use FieldValue.serverTimestamp() to custom model class in android

After lots of research i found a solution for this.

 @ServerTimestamp
 private Date timestamp;

 public Date getTimestamp() {
     return timestamp;
 }
 public void setTimestamp(Date timestamp) {
        this.timestamp = timestamp;
 }

and when calling this class

UserModel userModel = new UserModel();
userModel.setEmail(email);
userModel.setPassword(password);
userModel.setName(name);
userModel.setUid(uid);

insertUserDataToFireStore(userModel); 

This is the link where i found the solution Click here