code: public void setPrimaryKey(int primaryKey) 
     throws IllegalArgumentException
     {
  
        if (primaryKey <= NULL)
        {
           this.primaryKey = Data.NULL;
        }
        else
        {
  
           this.primaryKey = primaryKey;
  
           //resetNew();
  
           return;
        }
     }
docs: Set primary key
  @param primaryKey the primary key to set
  @throws IllegalArgumentException primary key is < 1