Here is a code snippet from the Human Task Example in jbpm-examples that accesses content via the API. Is this what you have in mind?
BlockingGetTaskResponseHandler getTaskResponseHandler = new BlockingGetTaskResponseHandler();
taskClient.getTask(task4.getId(), getTaskResponseHandler);
Task task = getTaskResponseHandler.getTask();
BlockingGetContentResponseHandler getContentResponseHandler = new BlockingGetContentResponseHandler();
taskClient.getContent(task.getTaskData().getDocumentContentId(), getContentResponseHandler);
Content content = getContentResponseHandler.getContent();
ByteArrayInputStream bis = new ByteArrayInputStream(content.getContent());
ObjectInputStream in;
try {
in = new ObjectInputStream(bis);
Object result = in.readObject();
in.close();
Map<?, ?> map = (Map<?, ?>) result;
for (Map.Entry<?, ?> entry: map.entrySet()) {
System.out.println(entry.getKey() + " = " + entry.getValue());
}
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}