How to get RTC work item attribute data using java API?

I am using below code and it returns some information about "Filed Against" attribute. But there I am not able to find attribute data. Please help

IAttribute someAttribute= workItemClient.findAttribute(projectAreaHandle, workItem.CATEGORY_PROPERTY, monitor);

Using below code to find out the work item by Id :

workItemClient = (IWorkItemClient) repo.getClientLibrary(IWorkItemClient.class);
                int id = new Integer("339406").intValue();  
                IWorkItem workItem = workItemClient.findWorkItemById(id, IWorkItem.FULL_PROFILE, monitor);

using this work item I want to fetch parent and children like Epic and story work items related to the work item. And then there attributes like story status, story planned for etc.

From this thread:

You can't just put a string in there, I think.
You have to find the category object from the string and then put in the ICategory object.

That means:

private static String CATEGORY_NAME = "UI1"; 
List<ICategory> findCategories = workItemCommon.findCategories(projectArea, ICategory.FULL_PROFILE, monitor); 
    for(ICategory category : findCategories) { 
          if(category.getName().contains(CATEGORY_NAME)){ 
              filedAgainstAttribute = QueryableAttributes.getFactory(IWorkItem.ITEM_TYPE).findAttribute(projectArea, IWorkItem.CATEGORY_PROPERTY, auditableClient, monitor); 
                    filedAgainstExpression = new AttributeExpression(filedAgainstAttribute, AttributeOperation.EQUALS, category);
       } 
  }